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2179 lines
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HTML
2179 lines
79 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
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<HEAD>
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<TITLE>Apache Server Frequently Asked Questions</TITLE>
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<!--#include virtual="header.html" -->
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<H1 ALIGN="CENTER">Apache Server Frequently Asked Questions</H1>
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<P>
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$Revision: 1.106 $ ($Date: 1998/02/11 15:14:33 $)
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</P>
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<P>
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The latest version of this FAQ is always available from the main
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Apache web site, at
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<<A
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HREF="http://www.apache.org/docs/misc/FAQ.html"
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REL="Help"
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><SAMP>http://www.apache.org/docs/misc/FAQ.html</SAMP></A>>.
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</P>
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<!-- Notes about changes: -->
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<!-- - If adding a relative link to another part of the -->
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<!-- documentation, *do* include the ".html" portion. There's a -->
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<!-- good chance that the user will be reading the documentation -->
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<!-- on his own system, which may not be configured for -->
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<!-- multiviews. -->
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<!-- - When adding items, make sure they're put in the right place -->
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<!-- - *Don't* use <PRE></PRE> blocks - they don't appear -->
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<!-- correctly in a reliable way when this is converted to text -->
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<!-- with Lynx. Use <DL><DD><CODE>xxx<BR>xx</CODE></DD></DL> -->
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<!-- blocks inside a <P></P> instead. This is necessary to get -->
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<!-- the horizontal and vertical indenting right. -->
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<!-- - Don't forget to include an HR tag after the last /P tag -->
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<!-- but before the /LI in an item. -->
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<P>
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If you are reading a text-only version of this FAQ, you may find numbers
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enclosed in brackets (such as "[12]"). These refer to the list of
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reference URLs to be found at the end of the document. These references
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do not appear, and are not needed, for the hypertext version.
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</P>
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<H2>The Questions</H2>
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<!-- Stuff to Add: -->
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<!-- - can't bind to port 80 -->
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<!-- - permission denied -->
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<!-- - address already in use -->
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<!-- - mod_auth & passwd lines "user:pw:.*" - ++1st colon onward is -->
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<!-- treated as pw, not just ++1st to --2nd. -->
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<!-- - SSL: -->
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<!-- - Can I use Apache-SSL for free in Canada? -->
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<!-- - Why can't I use Apache-SSL in the U.S.? -->
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<!-- - How can I found out how many visitors my site gets? -->
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<!-- - How do I add a counter? -->
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<!-- - How do I configure Apache as a proxy? -->
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<!-- - What browsers support HTTP/1.1? -->
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<!-- - What's the point of vhosts-by-name is there aren't any -->
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<!-- HTTP/1.1 browsers? -->
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<!-- - Is there an Apache for W95/WNT? -->
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<!-- - Why does Apache die when a vhost can't be DNS-resolved? -->
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<!-- - Why do I get "send lost connection" messages in my error -->
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<!-- log? -->
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<!-- - specifically consider .pdf files which seem to cause this -->
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<!-- a lot when accessed via the plugin ... and also mention -->
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<!-- how range-requests can cause bytes served < file size -->
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<!-- - Why do directory indexes appear as garbage? (A: -lucb) -->
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<!-- - How do I add a footer to all pages offered by my server? -->
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<!-- - Fix midi question; a bigger problem than midi vs. x-midi is -->
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<!-- the simple fact that older versions of Apache (and new ones -->
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<!-- that have been upgraded without upgrading the mime.types -->
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<!-- file) don't have the type listed at all. -->
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<!-- - Why is my .htaccess ignored? -->
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<!-- - RewriteRule /~fraggle/* /cgi-bin/fraggle.pl does not work -->
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<UL>
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<LI><STRONG>Background</STRONG>
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<OL START=1>
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<LI><A HREF="#what">What is Apache?</A>
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</LI>
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<LI><A HREF="#why">Why was Apache created?</A>
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</LI>
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<LI><A HREF="#relate">How does The Apache Group's work relate to
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other servers?</A>
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</LI>
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<LI><A HREF="#name">Why the name "Apache"?</A>
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</LI>
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<LI><A HREF="#compare">OK, so how does Apache compare to other servers?</A>
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</LI>
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<LI><A HREF="#tested">How thoroughly tested is Apache?</A>
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</LI>
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<LI><A HREF="#future">What are the future plans for Apache?</A>
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</LI>
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<LI><A HREF="#support">Whom do I contact for support?</A>
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</LI>
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<LI><A HREF="#more">Is there any more information on Apache?</A>
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</LI>
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<LI><A HREF="#where">Where can I get Apache?</A>
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</LI>
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</OL>
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</LI>
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<LI><STRONG>Technical Questions</STRONG>
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<OL START=11>
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<LI><A HREF="#what2do">"Why can't I ...? Why won't ...
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work?" What to do in case of problems</A>
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</LI>
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<LI><A HREF="#compatible">How compatible is Apache with my existing
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NCSA 1.3 setup?</A>
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</LI>
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<LI><A HREF="#CGIoutsideScriptAlias">How do I enable CGI execution
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in directories other than the ScriptAlias?</A>
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</LI>
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<LI><A HREF="#premature-script-headers">What does it mean when my
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CGIs fail with "<SAMP>Premature end of script
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headers</SAMP>"?</A>
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</LI>
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<LI><A HREF="#ssi-part-i">How do I enable SSI (parsed HTML)?</A>
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</LI>
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<LI><A HREF="#ssi-part-ii">Why don't my parsed files get cached?</A>
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</LI>
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<LI><A HREF="#ssi-part-iii">How can I have my script output parsed?</A>
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</LI>
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<LI><A HREF="#proxy">Does or will Apache act as a Proxy server?</A>
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</LI>
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<LI><A HREF="#multiviews">What are "multiviews"?</A>
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</LI>
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<LI><A HREF="#fdlim">Why can't I run more than <<EM>n</EM>>
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virtual hosts?</A>
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</LI>
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<LI><A HREF="#freebsd-setsize">Can I increase FD_SETSIZE on FreeBSD?</A>
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</LI>
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<LI><A HREF="#limitGET">Why do I keep getting "access denied" for
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form POST requests?</A>
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</LI>
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<LI><A HREF="#passwdauth">Can I use my <SAMP>/etc/passwd</SAMP> file
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for Web page authentication?</A>
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</LI>
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<LI><A HREF="#errordoc401">Why doesn't my <CODE>ErrorDocument
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401</CODE> work?</A>
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</LI>
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<LI><A HREF="#errordocssi">How can I use <CODE>ErrorDocument</CODE>
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and SSI to simplify customized error messages?</A>
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</LI>
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<LI><A HREF="#setgid">Why do I get "<SAMP>setgid: Invalid
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argument</SAMP>" at startup?</A>
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</LI>
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<LI><A HREF="#cookies1">Why does Apache send a cookie on every response?</A>
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</LI>
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<LI><A HREF="#cookies2">Why don't my cookies work, I even compiled in
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<SAMP>mod_cookies</SAMP>?</A>
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</LI>
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<LI><A HREF="#jdk1-and-http1.1">Why do my Java app[let]s give me plain text
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when I request an URL from an Apache server?</A>
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</LI>
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<LI><A HREF="#putsupport">Why can't I publish to my Apache server
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using PUT on Netscape Gold and other programs?</A>
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</LI>
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<LI><A HREF="#fastcgi">Why isn't FastCGI included with Apache any
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more?</A>
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</LI>
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<LI><A HREF="#nodelay">Why am I getting "<SAMP>httpd: could not
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set socket option TCP_NODELAY</SAMP>" in my error log?</A>
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</LI>
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<LI><A HREF="#peerreset">Why am I getting "<SAMP>connection
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reset by peer</SAMP>" in my error log?</A>
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</LI>
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<LI><A HREF="#nph-scripts">How can I get my script's output without
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Apache buffering it? Why doesn't my server push work?</A>
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</LI>
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<LI><A HREF="#linuxiovec">Why do I get complaints about redefinition
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of "<CODE>struct iovec</CODE>" when compiling under Linux?</A>
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</LI>
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<LI><A HREF="#wheres-the-dump">The errorlog says Apache dumped core,
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but where's the dump file?</A>
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</LI>
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<LI><A HREF="#dnsauth">Why isn't restricting access by host or domain name
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working correctly?</A>
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</LI>
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<LI><A HREF="#SSL-i">Why doesn't Apache include SSL?</A>
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</LI>
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<LI><A HREF="#HPUX-core">Why do I get core dumps under HPUX using
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HP's ANSI C compiler?</A>
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</LI>
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<LI><A HREF="#midi">How do I get Apache to send a MIDI file so the
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browser can play it?</A>
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</LI>
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<LI><A HREF="#cantbuild">Why won't Apache compile with my
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system's <SAMP>cc</SAMP>?</A>
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</LI>
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<LI><A HREF="#addlog">How do I add browsers and referrers to my
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logs?</A>
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</LI>
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<LI><A HREF="#bind8.1">Why do I get an error about an undefined
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reference to "<SAMP>__inet_ntoa</SAMP>" or other
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<SAMP>__inet_*</SAMP> symbols?</A>
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</LI>
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<LI><A HREF="#set-servername">Why does accessing directories only work
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when I include the trailing "/"
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(<EM>e.g.</EM>, <SAMP>http://foo.domain.com/~user/</SAMP>) but
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not when I omit it
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(<EM>e.g.</EM>, <SAMP>http://foo.domain.com/~user</SAMP>)?</A>
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</LI>
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<LI><A HREF="#user-authentication">How do I set up Apache to require
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a username and password to access certain documents?</A>
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</LI>
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<LI><A HREF="#remote-user-var">Why is the environment variable
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<SAMP>REMOTE_USER</SAMP> not set?</A>
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</LI>
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<LI><A HREF="#remote-auth-only">How do I set up Apache to allow access
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to certain documents only if a site is either a local site
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<EM>or</EM> the user supplies a password and username?</A>
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</LI>
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<LI><A HREF="#no-info-directives">Why doesn't mod_info list any
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directives?</A>
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<LI><A HREF="#linux-shmget">When I run it under Linux I get "shmget:
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function not found", what should I do?</A>
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</LI>
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<LI><A HREF="#authauthoritative">Why does my authentication give
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me a server error?</A>
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<LI><A HREF="#auth-on-same-machine">Do I have to keep the (mSQL)
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authentication information on the same machine?</A>
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</LI>
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<LI><A HREF="#msql-slow">Why is my mSQL authentication terribly slow?</A>
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</LI>
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<LI><A HREF="#rewrite-more-config">Where can I find mod_rewrite rulesets
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which already solve particular URL-related problems?</A>
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</LI>
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<LI><A HREF="#rewrite-article">Where can I find any published information about
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URL-manipulations and mod_rewrite?</A>
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</LI>
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<LI><A HREF="#rewrite-complexity">Why is mod_rewrite so difficult to learn
|
|
and seems so complicated?</A>
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</LI>
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<LI><A HREF="#rewrite-dontwork">What can I do if my RewriteRules don't work
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as expected?</A>
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</LI>
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<LI><A HREF="#rewrite-prefixdocroot">Why don't some of my URLs get
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prefixed with DocumentRoot when using mod_rewrite?</A>
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</LI>
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<LI><A HREF="#rewrite-nocase">How can I make all my URLs case-insensitive
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with mod_rewrite?</A>
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</LI>
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<LI><A HREF="#rewrite-virthost">Why are RewriteRules in my VirtualHost
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parts ignored?</A>
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</LI>
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<LI><A HREF="#rewrite-envwhitespace">How can I use strings with whitespaces
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in RewriteRule's ENV flag?</A>
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</LI>
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<LI><A HREF="#cgi-spec">Where can I find the "CGI
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specification"?</A>
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</LI>
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<LI><A HREF="#year2000">Is Apache Year 2000 compliant?</A>
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</LI>
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<LI><A HREF="#namevhost">I upgraded to Apache 1.3b and now my
|
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virtual hosts don't work!</A>
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</LI>
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</OL>
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</LI>
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</UL>
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<HR>
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<H2>The Answers</H2>
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<H3>
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Background
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</H3>
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<OL START=1>
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<LI><A NAME="what">
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<STRONG>What is Apache?</STRONG>
|
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</A>
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<P>
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Apache was originally based on code and ideas found in the most
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popular HTTP server of the time.. NCSA httpd 1.3 (early 1995). It has
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since evolved into a far superior system which can rival (and probably
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surpass) almost any other UNIX based HTTP server in terms of functionality,
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efficiency and speed.
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</P>
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<P>
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Since it began, it has been completely rewritten, and includes many new
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features. Apache is, as of January 1997, the most popular WWW server on
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the Internet, according to the
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<A
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HREF="http://www.netcraft.com/Survey/"
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>Netcraft Survey</A>.
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</P>
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<HR>
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</LI>
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<LI><A NAME="why">
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<STRONG>Why was Apache created?</STRONG>
|
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</A>
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<P>
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To address the concerns of a group of WWW providers and part-time httpd
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programmers that httpd didn't behave as they wanted it to behave.
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Apache is an entirely volunteer effort, completely funded by its
|
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members, not by commercial sales.
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</P>
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<HR>
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</LI>
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<LI><A NAME="relate">
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<STRONG>How does The Apache Group's work relate to other
|
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server efforts, such as NCSA's?</STRONG>
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</A>
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<P>
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We, of course, owe a great debt to NCSA and their programmers for
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making the server Apache was based on. We now, however, have our own
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server, and our project is mostly our own. The Apache Project is an
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entirely independent venture.
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</P>
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<HR>
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</LI>
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<LI><A NAME="name">
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<STRONG>Why the name "Apache"?</STRONG>
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</A>
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<P>
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A cute name which stuck. Apache is "<STRONG>A
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PA</STRONG>t<STRONG>CH</STRONG>y server". It was
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based on some existing code and a series of "patch files".
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</P>
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<HR>
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</LI>
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<LI><A NAME="compare">
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<STRONG>OK, so how does Apache compare to other servers?</STRONG>
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</A>
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<P>
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For an independent assessment, see
|
|
<A
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HREF="http://webcompare.internet.com/chart.html"
|
|
>Web Compare</A>'s
|
|
comparison chart.
|
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</P>
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<P>
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Apache has been shown to be substantially faster than many other
|
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free servers. Although certain commercial servers have claimed to
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surpass Apache's speed (it has not been demonstrated that any of these
|
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"benchmarks" are a good way of measuring WWW server speed at any
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rate), we feel that it is better to have a mostly-fast free server
|
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than an extremely-fast server that costs thousands of dollars. Apache
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is run on sites that get millions of hits per day, and they have
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experienced no performance difficulties.
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</P>
|
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<HR>
|
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</LI>
|
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<LI><A NAME="tested">
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<STRONG>How thoroughly tested is Apache?</STRONG>
|
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</A>
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<P>
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Apache is run on over 500,000 Internet servers (as of July 1997). It has
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been tested thoroughly by both developers and users. The Apache Group
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maintains rigorous standards before releasing new versions of their
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server, and our server runs without a hitch on over one third of all
|
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WWW servers available on the Internet. When bugs do show up, we
|
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release patches and new versions as soon as they are available.
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</P>
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<P>
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|
The Apache project's web site includes a page with a partial list of
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<A
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HREF="http://www.apache.org/info/apache_users.html"
|
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>sites running Apache</A>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="future">
|
|
<STRONG>What are the future plans for Apache?</STRONG>
|
|
</A>
|
|
<P>
|
|
<UL>
|
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<LI>to continue as a public domain HTTP server,
|
|
</LI>
|
|
<LI>to keep up with advances in HTTP protocol and web developments in
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|
general,
|
|
</LI>
|
|
<LI>to collect suggestions for fixes/improvements from its users,
|
|
</LI>
|
|
<LI>to respond to needs of large volume providers as well as
|
|
occasional users.
|
|
</LI>
|
|
</UL>
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="support">
|
|
<STRONG>Whom do I contact for support?</STRONG>
|
|
</A>
|
|
<P>
|
|
There is no official support for Apache. None of the developers want to
|
|
be swamped by a flood of trivial questions that can be resolved elsewhere.
|
|
Bug reports and suggestions should be sent <EM>via</EM>
|
|
<A
|
|
HREF="http://www.apache.org/bug_report.html"
|
|
>the bug report page</A>.
|
|
Other questions should be directed to the
|
|
<A
|
|
HREF="news:comp.infosystems.www.servers.unix"
|
|
><SAMP>comp.infosystems.www.servers.unix</SAMP></A>
|
|
newsgroup, where some of the Apache team lurk,
|
|
in the company of many other httpd gurus who should be able
|
|
to help.
|
|
</P>
|
|
<P>
|
|
Commercial support for Apache is, however, available from a number
|
|
of third parties.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="more">
|
|
<STRONG>Is there any more information available on
|
|
Apache?</STRONG>
|
|
</A>
|
|
<P>
|
|
Indeed there is. See the main
|
|
<A
|
|
HREF="http://www.apache.org/"
|
|
>Apache web site</A>.
|
|
There is also a regular electronic publication called
|
|
<A
|
|
HREF="http://www.apacheweek.com/"
|
|
REL="Help"
|
|
><CITE>Apache Week</CITE></A>
|
|
available. Links to relevant <CITE>Apache Week</CITE> articles are
|
|
included below where appropriate. There are also some
|
|
<A
|
|
HREF="http://www.apache.org/info/apache_books.html"
|
|
>Apache-specific books</A> available.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="where">
|
|
<STRONG>Where can I get Apache?</STRONG>
|
|
</A>
|
|
<P>
|
|
You can find out how to download the source for Apache at the
|
|
project's
|
|
<A
|
|
HREF="http://www.apache.org/"
|
|
>main web page</A>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
</OL>
|
|
<H3>
|
|
Technical Questions
|
|
</H3>
|
|
<OL START=11>
|
|
<LI><A NAME="what2do">
|
|
<STRONG>"Why can't I ...? Why won't ... work?" What to
|
|
do in case of problems</STRONG>
|
|
</A>
|
|
<P>
|
|
If you are having trouble with your Apache server software, you should
|
|
take the following steps:
|
|
</P>
|
|
<OL>
|
|
<LI><STRONG>Check the errorlog!</STRONG>
|
|
<P>
|
|
Apache tries to be helpful when it encounters a problem. In many
|
|
cases, it will provide some details by writing one or messages to
|
|
the server error log. Sometimes this is enough for you to diagnose
|
|
& fix the problem yourself (such as file permissions or the like).
|
|
The default location of the error log is
|
|
<SAMP>/usr/local/apache/logs/error_log</SAMP>, but see the
|
|
<A
|
|
HREF="../mod/core.html#errorlog"
|
|
><SAMP>ErrorLog</SAMP></A>
|
|
directive in your config files for the location on your server.
|
|
</P>
|
|
</LI>
|
|
<LI><STRONG>Check the
|
|
<A
|
|
HREF="http://www.apache.org/docs/misc/FAQ.html"
|
|
>FAQ</A>!</STRONG>
|
|
<P>
|
|
The latest version of the Apache Frequently-Asked Questions list can
|
|
always be found at the main Apache web site.
|
|
</P>
|
|
</LI>
|
|
<LI><STRONG>Check the Apache bug database</STRONG>
|
|
<P>
|
|
Most problems that get reported to The Apache Group are recorded in
|
|
the
|
|
<A
|
|
HREF="http://bugs.apache.org/"
|
|
>bug database</A>.
|
|
<EM><STRONG>Please</STRONG> check the existing reports, open
|
|
<STRONG>and</STRONG> closed, before adding one.</EM> If you find
|
|
that your issue has already been reported, please <EM>don't</EM> add
|
|
a "me, too" report. If the original report isn't closed
|
|
yet, we suggest that you check it periodically. You might also
|
|
consider contacting the original submitter, because there may be an
|
|
email exchange going on about the issue that isn't getting recorded
|
|
in the database.
|
|
</P>
|
|
</LI>
|
|
<LI><STRONG>Ask in the <SAMP>comp.infosystems.www.servers.unix</SAMP>
|
|
USENET newsgroup</STRONG>
|
|
<P>
|
|
A lot of common problems never make it to the bug database because
|
|
there's already high Q&A traffic about them in the
|
|
<A
|
|
HREF="news:comp.infosystems.www.servers.unix"
|
|
><SAMP>comp.infosystems.www.servers.unix</SAMP></A>
|
|
newsgroup. Many Apache users, and some of the developers, can be
|
|
found roaming its virtual halls, so it is suggested that you seek
|
|
wisdom there. The chances are good that you'll get a faster answer
|
|
there than from the bug database, even if you <EM>don't</EM> see
|
|
your question already posted.
|
|
</P>
|
|
</LI>
|
|
<LI><STRONG>If all else fails, report the problem in the bug
|
|
database</STRONG>
|
|
<P>
|
|
If you've gone through those steps above that are appropriate and
|
|
have obtained no relief, then please <EM>do</EM> let The Apache
|
|
Group know about the problem by
|
|
<A
|
|
HREF="http://www.apache.org/bug_report.html"
|
|
>logging a bug report</A>.
|
|
</P>
|
|
<P>
|
|
If your problem involves the server crashing and generating a core
|
|
dump, please include a backtrace (if possible). As an example,
|
|
</P>
|
|
<P>
|
|
<DL>
|
|
<DD><CODE># cd <EM>ServerRoot</EM><BR>
|
|
# dbx httpd core<BR>
|
|
(dbx) where</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
(Substitute the appropriate locations for your
|
|
<SAMP>ServerRoot</SAMP> and your <SAMP>httpd</SAMP> and
|
|
<SAMP>core</SAMP> files. You may have to use <CODE>gdb</CODE>
|
|
instead of <CODE>dbx</CODE>.)
|
|
</P>
|
|
</LI>
|
|
</OL>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="compatible">
|
|
<STRONG>How compatible is Apache with my existing NCSA 1.3
|
|
setup?</STRONG>
|
|
</A>
|
|
<P>
|
|
Apache attempts to offer all the features and configuration options
|
|
of NCSA httpd 1.3, as well as many of the additional features found in
|
|
NCSA httpd 1.4 and NCSA httpd 1.5.
|
|
</P>
|
|
<P>
|
|
NCSA httpd appears to be moving toward adding experimental features
|
|
which are not generally required at the moment. Some of the experiments
|
|
will succeed while others will inevitably be dropped. The Apache
|
|
philosophy is to add what's needed as and when it is needed.
|
|
</P>
|
|
<P>
|
|
Friendly interaction between Apache and NCSA developers should ensure
|
|
that fundamental feature enhancements stay consistent between the two
|
|
servers for the foreseeable future.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="CGIoutsideScriptAlias">
|
|
<STRONG>How do I enable CGI execution in directories other than
|
|
the ScriptAlias?</STRONG>
|
|
</A>
|
|
<P>
|
|
Apache recognizes all files in a directory named as a
|
|
<A
|
|
HREF="../mod/mod_alias.html#scriptalias"
|
|
><SAMP>ScriptAlias</SAMP></A>
|
|
as being eligible for execution rather than processing as normal
|
|
documents. This applies regardless of the file name, so scripts in a
|
|
ScriptAlias directory don't need to be named
|
|
"<SAMP>*.cgi</SAMP>" or "<SAMP>*.pl</SAMP>" or
|
|
whatever. In other words, <EM>all</EM> files in a ScriptAlias
|
|
directory are scripts, as far as Apache is concerned.
|
|
</P>
|
|
<P>
|
|
To persuade Apache to execute scripts in other locations, such as in
|
|
directories where normal documents may also live, you must tell it how
|
|
to recognize them - and also that it's okay to execute them. For
|
|
this, you need to use something like the
|
|
<A
|
|
HREF="../mod/mod_mime.html#addhandler"
|
|
><SAMP>AddHandler</SAMP></A>
|
|
directive.
|
|
</P>
|
|
<P>
|
|
<OL>
|
|
<LI>In an appropriate section of your server configuration files, add
|
|
a line such as
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>AddHandler cgi-script .cgi</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
The server will then recognize that all files in that location (and
|
|
its logical descendants) that end in "<SAMP>.cgi</SAMP>"
|
|
are script files, not documents.
|
|
</P>
|
|
</LI>
|
|
<LI>Make sure that the directory location is covered by an
|
|
<A
|
|
HREF="../mod/core.html#options"
|
|
><SAMP>Options</SAMP></A>
|
|
declaration that includes the <SAMP>ExecCGI</SAMP> option.
|
|
</LI>
|
|
</OL>
|
|
</P>
|
|
<P>
|
|
In some situations it can be not conform to your local policy to actually
|
|
allow all files named "<SAMP>*.cgi</SAMP>" to be executable.
|
|
Perhaps all you want is to enable a particular file in a normal directory to
|
|
be executable. This can be alternatively accomplished
|
|
<EM>via</EM>
|
|
<A
|
|
HREF="../mod/mod_rewrite.html"
|
|
><SAMP>mod_rewrite</SAMP></A>
|
|
and the following steps:
|
|
</P>
|
|
<P>
|
|
<OL>
|
|
<LI>Locally add to the corresponding <SAMP>.htaccess</SAMP> file a ruleset
|
|
similar to this one:
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>RewriteEngine on
|
|
<BR>
|
|
RewriteBase /~foo/bar/
|
|
<BR>
|
|
RewriteRule ^quux\.cgi$ - [T=application/x-httpd-cgi]</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
</LI>
|
|
<LI>Make sure that the directory location is covered by an
|
|
<A
|
|
HREF="../mod/core.html#options"
|
|
><SAMP>Options</SAMP></A>
|
|
declaration that includes the <SAMP>ExecCGI</SAMP> and
|
|
<SAMP>FollowSymLinks</SAMP> option.
|
|
</LI>
|
|
</OL>
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="premature-script-headers">
|
|
<STRONG>What does it mean when my CGIs fail with
|
|
"<SAMP>Premature end of script headers</SAMP>"?</STRONG>
|
|
</A>
|
|
<P>
|
|
It means just what it says: the server was expecting a complete set of
|
|
HTTP headers (one or more followed by a blank line), and didn't get
|
|
them.
|
|
</P>
|
|
<P>
|
|
The most common cause of this problem is the script dying before
|
|
sending the complete set of headers, or possibly any at all, to the
|
|
server. To see if this is the case, try running the script standalone
|
|
from an interactive session, rather than as a script under the server.
|
|
If you get error messages, this is almost certainly the cause of the
|
|
"premature end of script headers" message.
|
|
</P>
|
|
<P>
|
|
The second most common cause of this (aside from people not
|
|
outputting the required headers at all) is a result of an interaction
|
|
with Perl's output buffering. To make Perl flush its buffers
|
|
after each output statement, insert the following statements around
|
|
the <CODE>print</CODE> or <CODE>write</CODE> statements that send your
|
|
HTTP headers:
|
|
</P>
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>{<BR>
|
|
local ($oldbar) = $|;<BR>
|
|
$cfh = select (STDOUT);<BR>
|
|
$| = 1;<BR>
|
|
#<BR>
|
|
# print your HTTP headers here<BR>
|
|
#<BR>
|
|
$| = $oldbar;<BR>
|
|
select ($cfh);<BR>
|
|
}</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
This is generally only necessary when you are calling external
|
|
programs from your script that send output to stdout, or if there will
|
|
be a long delay between the time the headers are sent and the actual
|
|
content starts being emitted. To maximize performance, you should
|
|
turn buffer-flushing back <EM>off</EM> (with <CODE>$| = 0</CODE> or the
|
|
equivalent) after the statements that send the headers, as displayed
|
|
above.
|
|
</P>
|
|
<P>
|
|
If your script isn't written in Perl, do the equivalent thing for
|
|
whatever language you <EM>are</EM> using (<EM>e.g.</EM>, for C, call
|
|
<CODE>fflush()</CODE> after writing the headers).
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="ssi-part-i">
|
|
<STRONG>How do I enable SSI (parsed HTML)?</STRONG>
|
|
</A>
|
|
<P>
|
|
SSI (an acronym for Server-Side Include) directives allow static HTML
|
|
documents to be enhanced at run-time (<EM>e.g.</EM>, when delivered to
|
|
a client by Apache). The format of SSI directives is covered
|
|
in the <A HREF="../mod/mod_include.html">mod_include manual</A>;
|
|
suffice it to say that Apache supports not only SSI but
|
|
xSSI (eXtended SSI) directives.
|
|
</P>
|
|
<P>
|
|
Processing a document at run-time is called <EM>parsing</EM> it; hence
|
|
the term "parsed HTML" sometimes used for documents that
|
|
contain SSI instructions. Parsing tends to be <EM>extremely</EM>
|
|
resource-consumptive, and is not enabled by default. It can also
|
|
interfere with the cachability of your documents, which can put a
|
|
further load on your server. (see the
|
|
<A
|
|
HREF="#ssi-part-ii"
|
|
>next question</A>
|
|
for more information about this.)
|
|
</P>
|
|
<P>
|
|
To enable SSI processing, you need to
|
|
</P>
|
|
<UL>
|
|
<LI>Build your server with the
|
|
<A
|
|
HREF="../mod/mod_include.html"
|
|
><SAMP>mod_include</SAMP></A>
|
|
module. This is normally compiled in by default.
|
|
</LI>
|
|
<LI>Make sure your server configuration files have an
|
|
<A
|
|
HREF="../mod/core.html#options"
|
|
><SAMP>Options</SAMP></A>
|
|
directive which permits <SAMP>Includes</SAMP>.
|
|
</LI>
|
|
<LI>Make sure that the directory where you want the SSI documents to
|
|
live is covered by the "server-parsed" content handler,
|
|
either explicitly or in some ancestral location. That can be done
|
|
with the following
|
|
<A
|
|
HREF="../mod/mod_mime.html#addhandler"
|
|
><SAMP>AddHandler</SAMP></A>
|
|
directive:
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>AddHandler server-parsed .shtml</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
This indicates that all files ending in ".shtml" in that
|
|
location (or its descendants) should be parsed. Note that using
|
|
".html" will cause all normal HTML files to be parsed,
|
|
which may put an inordinate load on your server.
|
|
</LI>
|
|
</UL>
|
|
<P>
|
|
For additional information, see the <CITE>Apache Week</CITE> article
|
|
on
|
|
<A
|
|
HREF="http://www.apacheweek.com/features/ssi"
|
|
REL="Help"
|
|
><CITE>Using Server Side Includes</CITE></A>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="ssi-part-ii">
|
|
<STRONG>Why don't my parsed files get cached?</STRONG>
|
|
</A>
|
|
<P>
|
|
Since the server is performing run-time processing of your SSI
|
|
directives, which may change the content shipped to the client, it
|
|
can't know at the time it starts parsing what the final size of the
|
|
result will be, or whether the parsed result will always be the same.
|
|
This means that it can't generate <SAMP>Content-Length</SAMP> or
|
|
<SAMP>Last-Modified</SAMP> headers. Caches commonly work by comparing
|
|
the <SAMP>Last-Modified</SAMP> of what's in the cache with that being
|
|
delivered by the server. Since the server isn't sending that header
|
|
for a parsed document, whatever's doing the caching can't tell whether
|
|
the document has changed or not - and so fetches it again to be on the
|
|
safe side.
|
|
</P>
|
|
<P>
|
|
You can work around this in some cases by causing an
|
|
<SAMP>Expires</SAMP> header to be generated. (See the
|
|
<A
|
|
HREF="../mod/mod_expires.html"
|
|
REL="Help"
|
|
><SAMP>mod_expires</SAMP></A>
|
|
documentation for more details.) Another possibility is to use the
|
|
<A
|
|
HREF="../mod/mod_include.html#xbithack"
|
|
REL="Help"
|
|
><SAMP>XBitHack Full</SAMP></A>
|
|
mechanism, which tells Apache to send (under certain circumstances
|
|
detailed in the XBitHack directive description) a
|
|
<SAMP>Last-Modified</SAMP> header based upon the last modification
|
|
time of the file being parsed. Note that this may actually be lying
|
|
to the client if the parsed file doesn't change but the SSI-inserted
|
|
content does; if the included content changes often, this can result
|
|
in stale copies being cached.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="ssi-part-iii">
|
|
<STRONG>How can I have my script output parsed?</STRONG>
|
|
</A>
|
|
<P>
|
|
So you want to include SSI directives in the output from your CGI
|
|
script, but can't figure out how to do it?
|
|
The short answer is "you can't." This is potentially
|
|
a security liability and, more importantly, it can not be cleanly
|
|
implemented under the current server API. The best workaround
|
|
is for your script itself to do what the SSIs would be doing.
|
|
After all, it's generating the rest of the content.
|
|
</P>
|
|
<P>
|
|
This is a feature The Apache Group hopes to add in the next major
|
|
release after 1.3.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="proxy">
|
|
<STRONG>Does or will Apache act as a Proxy server?</STRONG>
|
|
</A>
|
|
<P>
|
|
Apache version 1.1 and above comes with a
|
|
<A
|
|
HREF="../mod/mod_proxy.html"
|
|
>proxy module</A>.
|
|
If compiled
|
|
in, this will make Apache act as a caching-proxy server.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="multiviews">
|
|
<STRONG>What are "multiviews"?</STRONG>
|
|
</A>
|
|
<P>
|
|
"Multiviews" is the general name given to the Apache
|
|
server's ability to provide language-specific document variants in
|
|
response to a request. This is documented quite thoroughly in the
|
|
<A
|
|
HREF="../content-negotiation.html"
|
|
REL="Help"
|
|
>content negotiation</A>
|
|
description page. In addition, <CITE>Apache Week</CITE> carried an
|
|
article on this subject entitled
|
|
"<A
|
|
HREF="http://www.apacheweek.com/features/negotiation"
|
|
REL="Help"
|
|
><CITE>Content Negotiation Explained</CITE></A>".
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="fdlim">
|
|
<STRONG>Why can't I run more than <<EM>n</EM>>
|
|
virtual hosts?</STRONG>
|
|
</A>
|
|
<P>
|
|
You are probably running into resource limitations in your
|
|
operating system. The most common limitation is the
|
|
<EM>per</EM>-process limit on <STRONG>file descriptors</STRONG>,
|
|
which is almost always the cause of problems seen when adding
|
|
virtual hosts. Apache often does not give an intuitive error
|
|
message because it is normally some library routine (such as
|
|
<CODE>gethostbyname()</CODE>) which needs file descriptors and
|
|
doesn't complain intelligibly when it can't get them.
|
|
</P>
|
|
<P>
|
|
Each log file requires a file descriptor, which means that if you are
|
|
using separate access and error logs for each virtual host, each
|
|
virtual host needs two file descriptors. Each
|
|
<A
|
|
HREF="../mod/core.html#listen"
|
|
><SAMP>Listen</SAMP></A>
|
|
directive also needs a file descriptor.
|
|
</P>
|
|
<P>
|
|
Typical values for <<EM>n</EM>> that we've seen are in
|
|
the neighborhood of 128 or 250. When the server bumps into the file
|
|
descriptor limit, it may dump core with a SIGSEGV, it might just
|
|
hang, or it may limp along and you'll see (possibly meaningful) errors
|
|
in the error log. One common problem that occurs when you run into
|
|
a file descriptor limit is that CGI scripts stop being executed
|
|
properly.
|
|
</P>
|
|
<P>
|
|
As to what you can do about this:
|
|
</P>
|
|
<OL>
|
|
<LI>Reduce the number of
|
|
<A
|
|
HREF="../mod/core.html#listen"
|
|
><SAMP>Listen</SAMP></A>
|
|
directives. If there are no other servers running on the machine
|
|
on the same port then you normally don't
|
|
need any Listen directives at all. By default Apache listens to
|
|
all addresses on port 80.
|
|
</LI>
|
|
<LI>Reduce the number of log files. You can use
|
|
<A
|
|
HREF="../mod/mod_log_config.html"
|
|
><SAMP>mod_log_config</SAMP></A>
|
|
to log all requests to a single log file while including the name
|
|
of the virtual host in the log file. You can then write a
|
|
script to split the logfile into separate files later if
|
|
necessary.
|
|
</LI>
|
|
<LI>Increase the number of file descriptors available to the server
|
|
(see your system's documentation on the <CODE>limit</CODE> or
|
|
<CODE>ulimit</CODE> commands). For some systems, information on
|
|
how to do this is available in the
|
|
<A
|
|
HREF="perf.html"
|
|
>performance hints</A>
|
|
page. There is a specific note for
|
|
<A HREF="#freebsd-setsize">FreeBSD</A> below.
|
|
</LI>
|
|
<LI>"Don't do that" - try to run with fewer virtual hosts
|
|
</LI>
|
|
<LI>Spread your operation across multiple server processes (using
|
|
<A
|
|
HREF="../mod/core.html#listen"
|
|
><SAMP>Listen</SAMP></A>
|
|
for example, but see the first point) and/or ports.
|
|
</LI>
|
|
</OL>
|
|
<P>
|
|
Since this is an operating-system limitation, there's not much else
|
|
available in the way of solutions.
|
|
</P>
|
|
<P>
|
|
As of 1.2.1 we have made attempts to work around various limitations
|
|
involving running with many descriptors.
|
|
<A HREF="descriptors.html">More information is available.</A>
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
|
|
<LI><A NAME="freebsd-setsize">
|
|
<STRONG>Can I increase <SAMP>FD_SETSIZE</SAMP> on FreeBSD?</STRONG>
|
|
</A>
|
|
<P>
|
|
On versions of FreeBSD before 3.0, the <SAMP>FD_SETSIZE</SAMP> define
|
|
defaults to 256. This means that you will have trouble usefully using
|
|
more than 256 file descriptors in Apache. This can be increased, but
|
|
doing so can be tricky.
|
|
|
|
If you are using a version prior to 2.2, you need to recompile your
|
|
kernel with a larger FD_SETSIZE. This can be done by adding a
|
|
line such as:
|
|
</P>
|
|
<DL>
|
|
<DD><CODE>options FD_SETSIZE <EM>nnn</EM></CODE>
|
|
</DD>
|
|
</DL>
|
|
<P>
|
|
To your kernel config file. Starting at version 2.2, this is no
|
|
longer necessary.
|
|
</P>
|
|
<P>
|
|
If you are using a version of 2.1-stable from after 1997/03/10 or
|
|
2.2 or 3.0-current from before 1997/06/28, there is a limit in
|
|
the resolver library that prevents it from using more file descriptors
|
|
than what FD_SETSIZE is set to when libc is compiled. To increase
|
|
this, you have to recompile libc with a higher FD_SETSIZE.
|
|
</P>
|
|
<P>
|
|
In FreeBSD 3.0, the default FD_SETSIZE has been increased to
|
|
1024 and the above limitation in the resolver library
|
|
has been removed.
|
|
</P>
|
|
<P>
|
|
After you deal with the appropriate changes above, you can increase
|
|
the setting of <SAMP>FD_SETSIZE</SAMP> at Apache compilation time
|
|
by adding "<SAMP>-DFD_SETSIZE=<EM>nnn</EM></SAMP>" to the
|
|
<SAMP>EXTRA_CFLAGS</SAMP> line in your <SAMP>Configuration</SAMP>
|
|
file.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
|
|
<LI><A NAME="limitGET">
|
|
<STRONG>Why do I keep getting "access denied" for form POST
|
|
requests?</STRONG>
|
|
</A>
|
|
<P>
|
|
The most common cause of this is a <SAMP><Limit></SAMP> section
|
|
that only names the <SAMP>GET</SAMP> method. Look in your
|
|
configuration files for something that resembles the following and
|
|
would affect the location where the POST-handling script resides:
|
|
</P>
|
|
<P>
|
|
<DL>
|
|
<DD><CODE><Limit GET>
|
|
<BR> :</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
Change that to <CODE><Limit GET POST></CODE> and the problem
|
|
will probably go away. Better yet, remove the
|
|
<CODE><Limit></CODE> and <CODE></Limit></CODE> lines
|
|
altogether unless you're <EM>specifically</EM> trying to limit by
|
|
method (<SAMP>GET</SAMP>, <SAMP>PUT</SAMP>, <EM>et cetera</EM>). If
|
|
you don't have a <CODE><Limit></CODE> container, the
|
|
restrictions apply equally to <EM>all</EM> methods.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="passwdauth">
|
|
<STRONG>Can I use my <SAMP>/etc/passwd</SAMP> file
|
|
for Web page authentication?</STRONG>
|
|
</A>
|
|
<P>
|
|
Yes, you can - but it's a <STRONG>very bad idea</STRONG>. Here are
|
|
some of the reasons:
|
|
</P>
|
|
<UL>
|
|
<LI>The Web technology provides no governors on how often or how
|
|
rapidly password (authentication failure) retries can be made. That
|
|
means that someone can hammer away at your system's
|
|
<SAMP>root</SAMP> password using the Web, using a dictionary or
|
|
similar mass attack, just as fast as the wire and your server can
|
|
handle the requests. Most operating systems these days include
|
|
attack detection (such as <EM>n</EM> failed passwords for the same
|
|
account within <EM>m</EM> seconds) and evasion (breaking the
|
|
connection, disabling the account under attack, disabling
|
|
<EM>all</EM> logins from that source, <EM>et cetera</EM>), but the
|
|
Web does not.
|
|
</LI>
|
|
<LI>An account under attack isn't notified (unless the server is
|
|
heavily modified); there's no "You have 19483 login
|
|
failures" message when the legitimate owner logs in.
|
|
</LI>
|
|
<LI>Without an exhaustive and error-prone examination of the server
|
|
logs, you can't tell whether an account has been compromised.
|
|
Detecting that an attack has occurred, or is in progress, is fairly
|
|
obvious, though - <EM>if</EM> you look at the logs.
|
|
</LI>
|
|
<LI>Web authentication passwords (at least for Basic authentication)
|
|
generally fly across the wire, and through intermediate proxy
|
|
systems, in what amounts to plain text. "O'er the net we
|
|
go/Caching all the way;/O what fun it is to surf/Giving my password
|
|
away!"
|
|
</LI>
|
|
<LI>Since HTTP is stateless, information about the authentication is
|
|
transmitted <EM>each and every time</EM> a request is made to the
|
|
server. Essentially, the client caches it after the first
|
|
successful access, and transmits it without asking for all
|
|
subsequent requests to the same server.
|
|
</LI>
|
|
<LI>It's relatively trivial for someone on your system to put up a
|
|
page that will steal the cached password from a client's cache
|
|
without them knowing. Can you say "password grabber"?
|
|
</LI>
|
|
</UL>
|
|
<P>
|
|
If you still want to do this in light of the above disadvantages, the
|
|
method is left as an exercise for the reader. It'll void your Apache
|
|
warranty, though, and you'll lose all accumulated UNIX guru points.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="errordoc401">
|
|
<STRONG>Why doesn't my <CODE>ErrorDocument 401</CODE> work?</STRONG>
|
|
</A>
|
|
<P>
|
|
You need to use it with a URL in the form
|
|
"<SAMP>/foo/bar</SAMP>" and not one with a method and
|
|
hostname such as "<SAMP>http://host/foo/bar</SAMP>". See the
|
|
<A
|
|
HREF="../mod/core.html#errordocument"
|
|
><SAMP>ErrorDocument</SAMP></A>
|
|
documentation for details. This was incorrectly documented in the past.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="errordocssi">
|
|
<STRONG>How can I use <CODE>ErrorDocument</CODE>
|
|
and SSI to simplify customized error messages?</STRONG>
|
|
</A>
|
|
<P>
|
|
Have a look at <A HREF="custom_errordocs.html">this document</A>.
|
|
It shows in example form how you can a combination of XSSI and
|
|
negotiation to tailor a set of <CODE>ErrorDocument</CODE>s to your
|
|
personal taste, and returning different internationalized error
|
|
responses based on the client's native language.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="setgid">
|
|
<STRONG>Why do I get "<SAMP>setgid: Invalid
|
|
argument</SAMP>" at startup?</STRONG>
|
|
</A>
|
|
<P>
|
|
Your
|
|
<A
|
|
HREF="../mod/core.html#group"
|
|
><SAMP>Group</SAMP></A>
|
|
directive (probably in <SAMP>conf/httpd.conf</SAMP>) needs to name a
|
|
group that actually exists in the <SAMP>/etc/group</SAMP> file (or
|
|
your system's equivalent).
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="cookies1">
|
|
<STRONG>Why does Apache send a cookie on every response?</STRONG>
|
|
</A>
|
|
<P>
|
|
Apache does <EM>not</EM> send automatically send a cookie on every
|
|
response, unless you have re-compiled it with the
|
|
<A
|
|
HREF="../mod/mod_cookies.html"
|
|
><SAMP>mod_cookies</SAMP></A>
|
|
module.
|
|
This module was distributed with Apache prior to 1.2.
|
|
This module may help track users, and uses cookies to do this. If
|
|
you are not using the data generated by <SAMP>mod_cookies</SAMP>, do
|
|
not compile it into Apache. Note that in 1.2 this module was renamed
|
|
to the more correct name
|
|
<A
|
|
HREF="../mod/mod_usertrack.html"
|
|
><SAMP>mod_usertrack</SAMP></A>,
|
|
and cookies
|
|
have to be specifically enabled with the
|
|
<A
|
|
HREF="../mod/mod_usertrack.html#cookietracking"
|
|
><SAMP>CookieTracking</SAMP></A>
|
|
directive.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="cookies2">
|
|
<STRONG>Why don't my cookies work, I even compiled in
|
|
<SAMP>mod_cookies</SAMP>?
|
|
</STRONG>
|
|
</A>
|
|
<P>
|
|
Firstly, you do <EM>not</EM> need to compile in
|
|
<SAMP>mod_cookies</SAMP> in order for your scripts to work (see the
|
|
<A
|
|
HREF="#cookies1"
|
|
>previous question</A>
|
|
for more about <SAMP>mod_cookies</SAMP>). Apache passes on your
|
|
<SAMP>Set-Cookie</SAMP> header fine, with or without this module. If
|
|
cookies do not work it will be because your script does not work
|
|
properly or your browser does not use cookies or is not set-up to
|
|
accept them.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="jdk1-and-http1.1">
|
|
<STRONG>Why do my Java app[let]s give me plain text when I request
|
|
an URL from an Apache server?</STRONG>
|
|
</A>
|
|
<P>
|
|
As of version 1.2, Apache is an HTTP/1.1 (HyperText Transfer Protocol
|
|
version 1.1) server. This fact is reflected in the protocol version
|
|
that's included in the response headers sent to a client when
|
|
processing a request. Unfortunately, low-level Web access classes
|
|
included in the Java Development Kit (JDK) version 1.0.2 expect to see
|
|
the version string "HTTP/1.0" and do not correctly interpret
|
|
the "HTTP/1.1" value Apache is sending (this part of the
|
|
response is a declaration of what the server can do rather than a
|
|
declaration of the dialect of the response). The result
|
|
is that the JDK methods do not correctly parse the headers, and
|
|
include them with the document content by mistake.
|
|
</P>
|
|
<P>
|
|
This is definitely a bug in the JDK 1.0.2 foundation classes from Sun,
|
|
and it has been fixed in version 1.1. However, the classes in
|
|
question are part of the virtual machine environment, which means
|
|
they're part of the Web browser (if Java-enabled) or the Java
|
|
environment on the client system - so even if you develop
|
|
<EM>your</EM> classes with a recent JDK, the eventual users might
|
|
encounter the problem.
|
|
The classes involved are replaceable by vendors implementing the
|
|
Java virtual machine environment, and so even those that are based
|
|
upon the 1.0.2 version may not have this problem.
|
|
</P>
|
|
<P>
|
|
In the meantime, a workaround is to tell
|
|
Apache to "fake" an HTTP/1.0 response to requests that come
|
|
from the JDK methods; this can be done by including a line such as the
|
|
following in your server configuration files:
|
|
</P>
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>BrowserMatch Java1.0 force-response-1.0
|
|
<BR>
|
|
BrowserMatch JDK/1.0 force-response-1.0</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
More information about this issue can be found in the
|
|
<A
|
|
HREF="http://www.apache.org/info/jdk-102.html"
|
|
><CITE>Java and HTTP/1.1</CITE></A>
|
|
page at the Apache web site.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="putsupport">
|
|
<STRONG>Why can't I publish to my Apache server using PUT on
|
|
Netscape Gold and other programs?</STRONG>
|
|
</A>
|
|
<P>
|
|
Because you need to install and configure a script to handle
|
|
the uploaded files. This script is often called a "PUT" handler.
|
|
There are several available, but they may have security problems.
|
|
Using FTP uploads may be easier and more secure, at least for now.
|
|
For more information, see the <CITE>Apache Week</CITE> article
|
|
<A
|
|
HREF="http://www.apacheweek.com/features/put"
|
|
><CITE>Publishing Pages with PUT</CITE></A>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="fastcgi">
|
|
<STRONG>Why isn't FastCGI included with Apache any more?</STRONG>
|
|
</A>
|
|
<P>
|
|
The simple answer is that it was becoming too difficult to keep the
|
|
version being included with Apache synchronized with the master copy
|
|
at the
|
|
<A
|
|
HREF="http://www.fastcgi.com/servers/apache/"
|
|
>FastCGI web site</A>. When a new version of Apache was released, the
|
|
version of the FastCGI module included with it would soon be out of date.
|
|
</P>
|
|
<P>
|
|
You can still obtain the FastCGI module for Apache from the master
|
|
FastCGI web site.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="nodelay">
|
|
<STRONG>Why am I getting "<SAMP>httpd: could not set socket
|
|
option TCP_NODELAY</SAMP>" in my error log?</STRONG>
|
|
</A>
|
|
<P>
|
|
This message almost always indicates that the client disconnected
|
|
before Apache reached the point of calling <CODE>setsockopt()</CODE>
|
|
for the connection. It shouldn't occur for more than about 1% of the
|
|
requests your server handles, and it's advisory only in any case.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="peerreset">
|
|
<STRONG>Why am I getting "<SAMP>connection reset by
|
|
peer</SAMP>" in my error log?</STRONG>
|
|
</A>
|
|
<P>
|
|
This is a normal message and nothing about which to be alarmed. It simply
|
|
means that the client canceled the connection before it had been
|
|
completely set up - such as by the end-user pressing the "Stop"
|
|
button. People's patience being what it is, sites with response-time
|
|
problems or slow network links may experiences this more than
|
|
high-capacity ones or those with large pipes to the network.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="nph-scripts">
|
|
<STRONG>How can I get my script's output without Apache buffering
|
|
it? Why doesn't my server push work?</STRONG>
|
|
</A>
|
|
<P>
|
|
In order to improve network performance, Apache buffers script output
|
|
into relatively large chunks. If you have a script that sends
|
|
information in bursts (eg. as partial-done messages in a multi-commit
|
|
database transaction or any type of server push), the client will
|
|
not necessarily get the output as the script is generating it.
|
|
</P>
|
|
<P>
|
|
To avoid this, Apache recognizes scripts whose names begin with
|
|
"<SAMP>nph-</SAMP>" as <EM>non-parsed-header</EM> scripts.
|
|
That is, Apache won't buffer their output, but connect it directly to
|
|
the socket going back to the client.
|
|
</P>
|
|
<P>
|
|
While this will probably do what you want, there <EM>are</EM> some
|
|
disadvantages to it:
|
|
</P>
|
|
<UL>
|
|
<LI><STRONG>YOU</STRONG> (the script) are responsible for generating
|
|
<STRONG>ALL</STRONG> of the HTTP headers, and no longer
|
|
<EM>just</EM> the "<SAMP>Content-type</SAMP>" or
|
|
"<SAMP>Location</SAMP>" headers
|
|
</LI>
|
|
<LI>Unless your script generates its output carefully, you will see a
|
|
performance penalty as excessive numbers of packets go back and forth
|
|
</LI>
|
|
</UL>
|
|
<P>
|
|
As an example how you might handle the former (in a Perl script):
|
|
</P>
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>if ($0 =~ m:^(.*/)*nph-[^/]*$:) {
|
|
<BR>
|
|
|
|
$HTTP_headers =
|
|
"HTTP/1.1 200 OK\015\012";
|
|
<BR>
|
|
|
|
$HTTP_headers .=
|
|
"Connection: close\015\012";
|
|
<BR>
|
|
|
|
print $HTTP_headers;
|
|
<BR>
|
|
}</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
and then follow with your normal non-<SAMP>nph</SAMP> headers.
|
|
</P>
|
|
<P>Note that in version 1.3, all CGI scripts will be unbuffered
|
|
so the only difference between nph scripts and normal scripts is
|
|
that nph scripts require the full HTTP headers to be sent.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="linuxiovec">
|
|
<STRONG>Why do I get complaints about redefinition
|
|
of "<CODE>struct iovec</CODE>" when
|
|
compiling under Linux?</STRONG>
|
|
</A>
|
|
<P>
|
|
This is a conflict between your C library includes and your kernel
|
|
includes. You need to make sure that the versions of both are matched
|
|
properly. There are two workarounds, either one will solve the problem:
|
|
</P>
|
|
<P>
|
|
<UL>
|
|
<LI>Remove the definition of <CODE>struct iovec</CODE> from your C
|
|
library includes. It is located in <CODE>/usr/include/sys/uio.h</CODE>.
|
|
<STRONG>Or,</STRONG>
|
|
</LI>
|
|
<LI>Add <CODE>-DNO_WRITEV</CODE> to the <CODE>EXTRA_CFLAGS</CODE>
|
|
line in your <SAMP>Configuration</SAMP> and reconfigure/rebuild.
|
|
This hurts performance and should only be used as a last resort.
|
|
</LI>
|
|
</UL>
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="wheres-the-dump">
|
|
<STRONG>The errorlog says Apache dumped core, but where's the dump
|
|
file?</STRONG>
|
|
</A>
|
|
<P>
|
|
In Apache version 1.2, the error log message
|
|
about dumped core includes the directory where the dump file should be
|
|
located. However, many Unixes do not allow a process that has
|
|
called <CODE>setuid()</CODE> to dump core for security reasons;
|
|
the typical Apache setup has the server started as root to bind to
|
|
port 80, after which it changes UIDs to a non-privileged user to
|
|
serve requests.
|
|
</P>
|
|
<P>
|
|
Dealing with this is extremely operating system-specific, and may
|
|
require rebuilding your system kernel. Consult your operating system
|
|
documentation or vendor for more information about whether your system
|
|
does this and how to bypass it. If there <EM>is</EM> a documented way
|
|
of bypassing it, it is recommended that you bypass it only for the
|
|
<SAMP>httpd</SAMP> server process if possible.
|
|
</P>
|
|
<P>
|
|
The canonical location for Apache's core-dump files is the
|
|
<A HREF="../mod/core.html#serverroot">ServerRoot</A>
|
|
directory. As of Apache version 1.3, the location can be set <EM>via</EM>
|
|
the
|
|
<A
|
|
HREF="../mod/core.html#coredumpdirectory"
|
|
><SAMP>CoreDumpDirectory</SAMP></A>
|
|
directive to a different directory. Make sure that this directory is
|
|
writable by the user the server runs as (as opposed to the user the server
|
|
is <EM>started</EM> as).
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="dnsauth">
|
|
<STRONG>Why isn't restricting access by host or domain name
|
|
working correctly?</STRONG>
|
|
</A>
|
|
<P>
|
|
Two of the most common causes of this are:
|
|
</P>
|
|
<OL>
|
|
<LI><STRONG>An error, inconsistency, or unexpected mapping in the DNS
|
|
registration</STRONG>
|
|
<BR>
|
|
This happens frequently: your configuration restricts access to
|
|
<SAMP>Host.FooBar.Com</SAMP>, but you can't get in from that host.
|
|
The usual reason for this is that <SAMP>Host.FooBar.Com</SAMP> is
|
|
actually an alias for another name, and when Apache performs the
|
|
address-to-name lookup it's getting the <EM>real</EM> name, not
|
|
<SAMP>Host.FooBar.Com</SAMP>. You can verify this by checking the
|
|
reverse lookup yourself. The easiest way to work around it is to
|
|
specify the correct host name in your configuration.
|
|
</LI>
|
|
<LI><STRONG>Inadequate checking and verification in your
|
|
configuration of Apache</STRONG>
|
|
<BR>
|
|
If you intend to perform access checking and restriction based upon
|
|
the client's host or domain name, you really need to configure
|
|
Apache to double-check the origin information it's supplied. You do
|
|
this by adding the <SAMP>-DMAXIMUM_DNS</SAMP> clause to the
|
|
<SAMP>EXTRA_CFLAGS</SAMP> definition in your
|
|
<SAMP>Configuration</SAMP> file. For example:
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>EXTRA_CFLAGS=-DMAXIMUM_DNS</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
This will cause Apache to be very paranoid about making sure a
|
|
particular host address is <EM>really</EM> assigned to the name it
|
|
claims to be. Note that this <EM>can</EM> incur a significant
|
|
performance penalty, however, because of all the name resolution
|
|
requests being sent to a nameserver.
|
|
</P>
|
|
</LI>
|
|
</OL>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="SSL-i">
|
|
<STRONG>Why doesn't Apache include SSL?</STRONG>
|
|
</A>
|
|
<P>
|
|
SSL (Secure Socket Layer) data transport requires encryption, and many
|
|
governments have restrictions upon the import, export, and use of
|
|
encryption technology. If Apache included SSL in the base package,
|
|
its distribution would involve all sorts of legal and bureaucratic
|
|
issues, and it would no longer be freely available. Also, some of
|
|
the technology required to talk to current clients using SSL is
|
|
patented by <A HREF="http://www.rsa.com/">RSA Data Security</A>,
|
|
who restricts its use without a license.
|
|
</P>
|
|
<P>
|
|
Some SSL implementations of Apache are available, however; see the
|
|
"<A
|
|
HREF="http://www.apache.org/related_projects.html"
|
|
>related projects</A>"
|
|
page at the main Apache web site.
|
|
</P>
|
|
<P>
|
|
You can find out more about this topic in the <CITE>Apache Week</CITE>
|
|
article about
|
|
<A
|
|
HREF="http://www.apacheweek.com/features/ssl"
|
|
REL="Help"
|
|
><CITE>Apache and Secure Transactions</CITE></A>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="HPUX-core">
|
|
<STRONG>Why do I get core dumps under HPUX using HP's ANSI
|
|
C compiler?</STRONG>
|
|
</A>
|
|
<P>
|
|
We have had numerous reports of Apache dumping core when compiled
|
|
with HP's ANSI C compiler using optimization. Disabling the compiler
|
|
optimization has fixed these problems.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="midi">
|
|
<STRONG>How do I get Apache to send a MIDI file so the browser can
|
|
play it?</STRONG>
|
|
</A>
|
|
<P>
|
|
Even though the registered MIME type for MIDI files is
|
|
<SAMP>audio/midi</SAMP>, some browsers are not set up to recognize it
|
|
as such; instead, they look for <SAMP>audio/x-midi</SAMP>. There are
|
|
two things you can do to address this:
|
|
</P>
|
|
<OL>
|
|
<LI>Configure your browser to treat documents of type
|
|
<SAMP>audio/midi</SAMP> correctly. This is the type that Apache
|
|
sends by default. This may not be workable, however, if you have
|
|
many client installations to change, or if some or many of the
|
|
clients are not under your control.
|
|
</LI>
|
|
<LI>Instruct Apache to send a different <SAMP>Content-type</SAMP>
|
|
header for these files by adding the following line to your server's
|
|
configuration files:
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>AddType audio/x-midi .mid .midi .kar</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
Note that this may break browsers that <EM>do</EM> recognize the
|
|
<SAMP>audio/midi</SAMP> MIME type unless they're prepared to also
|
|
handle <SAMP>audio/x-midi</SAMP> the same way.
|
|
</P>
|
|
</LI>
|
|
</OL>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="cantbuild">
|
|
<STRONG>Why won't Apache compile with my system's
|
|
<SAMP>cc</SAMP>?</STRONG>
|
|
</A>
|
|
<P>
|
|
If the server won't compile on your system, it is probably due to one
|
|
of the following causes:
|
|
</P>
|
|
<UL>
|
|
<LI><STRONG>The <SAMP>Configure</SAMP> script doesn't recognize your system
|
|
environment.</STRONG>
|
|
<BR>
|
|
This might be either because it's completely unknown or because
|
|
the specific environment (include files, OS version, <EM>et
|
|
cetera</EM>) isn't explicitly handled. If this happens, you may
|
|
need to port the server to your OS yourself.
|
|
</LI>
|
|
<LI><STRONG>Your system's C compiler is garbage.</STRONG>
|
|
<BR>
|
|
Some operating systems include a default C compiler that is either
|
|
not ANSI C-compliant or suffers from other deficiencies. The usual
|
|
recommendation in cases like this is to acquire, install, and use
|
|
<SAMP>gcc</SAMP>.
|
|
</LI>
|
|
<LI><STRONG>Your <SAMP>include</SAMP> files may be confused.</STRONG>
|
|
<BR>
|
|
In some cases, we have found that a compiler installation or system
|
|
upgrade has left the C header files in an inconsistent state. Make
|
|
sure that your include directory tree is in sync with the compiler and
|
|
the operating system.
|
|
</LI>
|
|
<LI><STRONG>Your operating system or compiler may be out of
|
|
revision.</STRONG>
|
|
<BR>
|
|
Software vendors (including those that develop operating systems)
|
|
issue new releases for a reason; sometimes to add functionality, but
|
|
more often to fix bugs that have been discovered. Try upgrading
|
|
your compiler and/or your operating system.
|
|
</LI>
|
|
</UL>
|
|
<P>
|
|
The Apache Group tests the ability to build the server on many
|
|
different platforms. Unfortunately, we can't test all of the OS
|
|
platforms there are. If you have verified that none of the above
|
|
issues is the cause of your problem, and it hasn't been reported
|
|
before, please submit a
|
|
<A
|
|
HREF="http://www.apache.org/bug_report.html"
|
|
>problem report</A>.
|
|
Be sure to include <EM>complete</EM> details, such as the compiler
|
|
& OS versions and exact error messages.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="addlog">
|
|
<STRONG>How do I add browsers and referrers to my logs?</STRONG>
|
|
</A>
|
|
<P>
|
|
Apache provides a couple of different ways of doing this. The
|
|
recommended method is to compile the
|
|
<A
|
|
HREF="../mod/mod_log_config.html"
|
|
><SAMP>mod_log_config</SAMP></A>
|
|
module into your configuration and use the
|
|
<A
|
|
HREF="../mod/mod_log_config.html#customlog"
|
|
><SAMP>CustomLog</SAMP></A>
|
|
directive.
|
|
</P>
|
|
<P>
|
|
You can either log the additional information in files other than your
|
|
normal transfer log, or you can add them to the records already being
|
|
written. For example:
|
|
</P>
|
|
<P>
|
|
<CODE>
|
|
CustomLog logs/access_log "%h %l %u %t \"%r\" %s %b \"%{Referer}i\" \"%{User-Agent}i\""
|
|
</CODE>
|
|
</P>
|
|
<P>
|
|
This will add the values of the <SAMP>User-agent:</SAMP> and
|
|
<SAMP>Referer:</SAMP> headers, which indicate the client and the
|
|
referring page, respectively, to the end of each line in the access
|
|
log.
|
|
</P>
|
|
<P>
|
|
You may want to check out the <CITE>Apache Week</CITE> article
|
|
entitled:
|
|
"<A
|
|
HREF="http://www.apacheweek.com/features/logfiles"
|
|
REL="Help"
|
|
><CITE>Gathering Visitor Information: Customising Your
|
|
Logfiles</CITE></A>".
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="bind8.1">
|
|
<STRONG>Why do I get an error about an undefined reference to
|
|
"<SAMP>__inet_ntoa</SAMP>" or other
|
|
<SAMP>__inet_*</SAMP> symbols?</STRONG>
|
|
</A>
|
|
<P>
|
|
If you have installed <A HREF="http://www.isc.org/bind.html">BIND-8</A>
|
|
then this is normally due to a conflict between your include files
|
|
and your libraries. BIND-8 installs its include files and libraries
|
|
<CODE>/usr/local/include/</CODE> and <CODE>/usr/local/lib/</CODE>, while
|
|
the resolver that comes with your system is probably installed in
|
|
<CODE>/usr/include/</CODE> and <CODE>/usr/lib/</CODE>. If
|
|
your system uses the header files in <CODE>/usr/local/include/</CODE>
|
|
before those in <CODE>/usr/include/</CODE> but you do not use the new
|
|
resolver library, then the two versions will conflict.
|
|
</P>
|
|
<P>
|
|
To resolve this, you can either make sure you use the include files
|
|
and libraries that came with your system or make sure to use the
|
|
new include files and libraries. Adding <CODE>-lbind</CODE> to the
|
|
<CODE>EXTRA_LDFLAGS</CODE> line in your <SAMP>Configuration</SAMP>
|
|
file, then re-running <SAMP>Configure</SAMP>, should resolve the
|
|
problem. (Apache versions 1.2.* and earlier use
|
|
<CODE>EXTRA_LFLAGS</CODE> instead.)
|
|
</P>
|
|
<P>
|
|
<STRONG>Note:</STRONG>As of BIND 8.1.1, the bind libraries and files are
|
|
installed under <SAMP>/usr/local/bind</SAMP> by default, so you
|
|
should not run into this problem. Should you want to use the bind
|
|
resolvers you'll have to add the following to the respective lines:
|
|
</P>
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>EXTRA_CFLAGS=-I/usr/local/bind/include
|
|
<BR>
|
|
EXTRA_LDFLAGS=-L/usr/local/bind/lib
|
|
<BR>
|
|
EXTRA_LIBS=-lbind</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="set-servername">
|
|
<STRONG>Why does accessing directories only work when I include
|
|
the trailing "/"
|
|
(<EM>e.g.</EM>, <SAMP>http://foo.domain.com/~user/</SAMP>)
|
|
but not when I omit it
|
|
(<EM>e.g.</EM>, <SAMP>http://foo.domain.com/~user</SAMP>)?</STRONG>
|
|
</A>
|
|
<P>
|
|
When you access a directory without a trailing "/", Apache needs
|
|
to send what is called a redirect to the client to tell it to
|
|
add the trailing slash. If it did not do so, relative URLs would
|
|
not work properly. When it sends the redirect, it needs to know
|
|
the name of the server so that it can include it in the redirect.
|
|
There are two ways for Apache to find this out; either it can guess,
|
|
or you can tell it. If your DNS is configured correctly, it can
|
|
normally guess without any problems. If it is not, however, then
|
|
you need to tell it.
|
|
</P>
|
|
<P>
|
|
Add a <A HREF="../mod/core.html#servername">ServerName</A> directive
|
|
to the config file to tell it what the domain name of the server is.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="user-authentication">
|
|
<STRONG>How do I set up Apache to require a username and
|
|
password to access certain documents?</STRONG>
|
|
</A>
|
|
<P>
|
|
There are several ways to do this; some of the more popular
|
|
ones are to use the <A HREF="../mod/mod_auth.html">mod_auth</A>,
|
|
<A HREF="../mod/mod_auth_db.html">mod_auth_db</A>, or
|
|
<A HREF="../mod/mod_auth_dbm.html">mod_auth_dbm</A> modules.
|
|
</P>
|
|
<P>
|
|
For an explanation on how to implement these restrictions, see
|
|
<A
|
|
HREF="http://www.apacheweek.com/"
|
|
><CITE>Apache Week</CITE></A>'s
|
|
articles on
|
|
<A
|
|
HREF="http://www.apacheweek.com/features/userauth"
|
|
><CITE>Using User Authentication</CITE></A>
|
|
or
|
|
<A
|
|
HREF="http://www.apacheweek.com/features/dbmauth"
|
|
><CITE>DBM User Authentication</CITE></A>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="remote-user-var">
|
|
<STRONG>Why is the environment variable
|
|
<SAMP>REMOTE_USER</SAMP> not set?</STRONG>
|
|
</A>
|
|
<P>
|
|
This variable is set and thus available in SSI or CGI scripts <STRONG>if and
|
|
only if</STRONG> the requested document was protected by access
|
|
authentication. For an explanation on how to implement these restrictions,
|
|
see
|
|
<A
|
|
HREF="http://www.apacheweek.com/"
|
|
><CITE>Apache Week</CITE></A>'s
|
|
articles on
|
|
<A
|
|
HREF="http://www.apacheweek.com/features/userauth"
|
|
><CITE>Using User Authentication</CITE></A>
|
|
or
|
|
<A
|
|
HREF="http://www.apacheweek.com/features/dbmauth"
|
|
><CITE>DBM User Authentication</CITE></A>.
|
|
</P>
|
|
<P>
|
|
Hint: When using a CGI script to receive the data of a HTML <SAMP>FORM</SAMP>
|
|
notice that protecting the document containing the <SAMP>FORM</SAMP> is not
|
|
sufficient to provide <SAMP>REMOTE_USER</SAMP> to the CGI script. You have
|
|
to protect the CGI script, too. Or alternatively only the CGI script (then
|
|
authentication happens only after filling out the form).
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="remote-auth-only">
|
|
<STRONG>How do I set up Apache to allow access to certain
|
|
documents only if a site is either a local site <EM>or</EM>
|
|
the user supplies a password and username?</STRONG>
|
|
</A>
|
|
<P>
|
|
Use the <A HREF="../mod/core.html#satisfy">Satisfy</A> directive,
|
|
in particular the <CODE>Satisfy Any</CODE> directive, to require
|
|
that only one of the access restrictions be met. For example,
|
|
adding the following configuration to a <SAMP>.htaccess</SAMP>
|
|
or server configuration file would restrict access to people who
|
|
either are accessing the site from a host under domain.com or
|
|
who can supply a valid username and password:
|
|
</P>
|
|
<P>
|
|
<DL>
|
|
<DD><CODE>deny from all
|
|
<BR>
|
|
allow from .domain.com
|
|
<BR>
|
|
AuthType Basic
|
|
<BR>
|
|
AuthUserFile /usr/local/apache/conf/htpasswd.users
|
|
<BR>
|
|
AuthName special directory
|
|
<BR>
|
|
require valid-user
|
|
<BR>
|
|
satisfy any</CODE>
|
|
</DD>
|
|
</DL>
|
|
</P>
|
|
<P>
|
|
See the <A HREF="#user-authentication">user authentication</A>
|
|
question and the <A HREF="../mod/mod_access.html">mod_access</A>
|
|
module for details on how the above directives work.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="no-info-directives">
|
|
<STRONG>Why doesn't mod_info list any directives?</STRONG>
|
|
</A>
|
|
<P>
|
|
The
|
|
<A
|
|
HREF="../mod/mod_info.html"
|
|
><SAMP>mod_info</SAMP></A>
|
|
module allows you to use a Web browser to see how your server is
|
|
configured. Among the information it displays is the list modules and
|
|
their configuration directives. The "current" values for
|
|
the directives are not necessarily those of the running server; they
|
|
are extracted from the configuration files themselves at the time of
|
|
the request. If the files have been changed since the server was last
|
|
reloaded, the display will will not match the values actively in use.
|
|
If the files and the path to the files are not readable by the user as
|
|
which the server is running (see the
|
|
<A
|
|
HREF="../mod/core.html#user"
|
|
><SAMP>User</SAMP></A>
|
|
directive), then <SAMP>mod_info</SAMP> cannot read them in order to
|
|
list their values. An entry <EM>will</EM> be made in the error log in
|
|
this event, however.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="linux-shmget">
|
|
<STRONG>When I run it under Linux I get "shmget:
|
|
function not found", what should I do?</STRONG>
|
|
</A>
|
|
<P>
|
|
Your kernel has been built without SysV IPC support. You will have to
|
|
rebuild the kernel with that support enabled (it's under the
|
|
"General Setup" submenu). Documentation for
|
|
kernel building is beyond the scope of this FAQ; you should consult
|
|
the
|
|
<A HREF="http://www.linuxhq.com/HOWTO/Kernel-HOWTO.html"
|
|
>Kernel HOWTO</A>,
|
|
or the documentation provided with your distribution, or a
|
|
<A HREF="http://www.linuxhq.com/HOWTO/META-FAQ.html"
|
|
>Linux newsgroup/mailing list</A>.
|
|
As a last-resort workaround, you can
|
|
comment out the <CODE>#define USE_SHMGET_SCOREBOARD</CODE>
|
|
definition in the
|
|
<SAMP>LINUX</SAMP> section of
|
|
<SAMP>src/conf.h</SAMP> and rebuild the server (prior to 1.3b4, simply
|
|
removing <CODE>#define HAVE_SHMGET</CODE> would have sufficed).
|
|
This will produce a server which is slower and less reliable.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="authauthoritative">
|
|
<STRONG>Why does my authentication give me a server error?</STRONG>
|
|
</A>
|
|
<P>
|
|
Under normal circumstances, the Apache access control modules will
|
|
pass unrecognized user IDs on to the next access control module in
|
|
line. Only if the user ID is recognized and the password is validated
|
|
(or not) will it give the usual success or "authentication
|
|
failed" messages.
|
|
</P>
|
|
<P>
|
|
However, if the last access module in line 'declines' the validation
|
|
request (because it has never heard of the user ID or because it is not
|
|
configured), the <SAMP>http_request</SAMP> handler will give one of
|
|
the following, confusing, errors:
|
|
</P>
|
|
<UL>
|
|
<LI><SAMP>check access</SAMP>
|
|
</LI>
|
|
<LI><SAMP>check user. No user file?</SAMP>
|
|
</LI>
|
|
<LI><SAMP>check access. No groups file?</SAMP>
|
|
</LI>
|
|
</UL>
|
|
<P>
|
|
This does <EM>not</EM> mean that you have to add an
|
|
'<SAMP>AuthUserFile /dev/null</SAMP>' line as some magazines suggest!
|
|
</P>
|
|
<P>
|
|
The solution is to ensure that at least the last module is authoritative
|
|
and <STRONG>CONFIGURED</STRONG>. By default, <SAMP>mod_auth</SAMP> is
|
|
authoritative and will give an OK/Denied, but only if it is configured
|
|
with the proper <SAMP>AuthUserFile</SAMP>. Likewise, if a valid group
|
|
is required. (Remember that the modules are processed in the reverse
|
|
order from that in which they appear in your compile-time
|
|
<SAMP>Configuration</SAMP> file.)
|
|
</P>
|
|
<P>
|
|
A typical situation for this error is when you are using the
|
|
<SAMP>mod_auth_dbm</SAMP>, <SAMP>mod_auth_msql</SAMP>,
|
|
<SAMP>mod_auth_mysql</SAMP>, <SAMP>mod_auth_anon</SAMP> or
|
|
<SAMP>mod_auth_cookie</SAMP> modules on their own. These are by
|
|
default <STRONG>not</STRONG> authoritative, and this will pass the
|
|
buck on to the (non-existent) next authentication module when the
|
|
user ID is not in their respective database. Just add the appropriate
|
|
'<SAMP><EM>XXX</EM>Authoritative yes</SAMP>' line to the configuration.
|
|
</P>
|
|
<P>
|
|
In general it is a good idea (though not terribly efficient) to have the
|
|
file-based <SAMP>mod_auth</SAMP> a module of last resort. This allows
|
|
you to access the web server with a few special passwords even if the
|
|
databases are down or corrupted. This does cost a
|
|
file open/seek/close for each request in a protected area.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="auth-on-same-machine">
|
|
<STRONG>Do I have to keep the (mSQL) authentication information
|
|
on the same machine?</STRONG>
|
|
</A>
|
|
<P>
|
|
Some organizations feel very strongly about keeping the authentication
|
|
information on a different machine than the webserver. With the
|
|
<SAMP>mod_auth_msql</SAMP>, <SAMP>mod_auth_mysql</SAMP>, and other SQL
|
|
modules connecting to (R)DBMses this is quite possible. Just configure
|
|
an explicit host to contact.
|
|
</P>
|
|
<P>
|
|
Be aware that with mSQL and Oracle, opening and closing these database
|
|
connections is very expensive and time consuming. You might want to
|
|
look at the code in the <SAMP>auth_*</SAMP> modules and play with the
|
|
compile time flags to alleviate this somewhat, if your RDBMS licences
|
|
allow for it.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="msql-slow">
|
|
<STRONG>Why is my mSQL authentication terribly slow?</STRONG>
|
|
</A>
|
|
<P>
|
|
You have probably configured the Host by specifying a FQHN,
|
|
and thus the <SAMP>libmsql</SAMP> will use a full blown TCP/IP socket
|
|
to talk to the database, rather than a fast internal device. The
|
|
<SAMP>libmsql</SAMP>, the mSQL FAQ, and the <SAMP>mod_auth_msql</SAMP>
|
|
documentation warn you about this. If you have to use different
|
|
hosts, check out the <SAMP>mod_auth_msql</SAMP> code for
|
|
some compile time flags which might - or might not - suit you.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-more-config">
|
|
<STRONG>Where can I find mod_rewrite rulesets which already solve
|
|
particular URL-related problems?</STRONG>
|
|
</A>
|
|
<P>
|
|
There is a collection of
|
|
<A
|
|
HREF="http://www.engelschall.com/pw/apache/rewriteguide/"
|
|
>Practical Solutions for URL-Manipulation</A>
|
|
where you can
|
|
find all typical solutions the author of
|
|
<A
|
|
HREF="../mod/mod_rewrite.html"
|
|
><SAMP>mod_rewrite</SAMP></A>
|
|
currently knows of. If you have more
|
|
interesting rulesets which solve particular problems not currently covered in
|
|
this document, send it to
|
|
<A
|
|
HREF="mailto:rse@apache.org"
|
|
>Ralf S. Engelschall</A>
|
|
for inclusion. The
|
|
other webmasters will thank you for avoiding the reinvention of the wheel.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-article">
|
|
<STRONG>Where can I find any published information about URL-manipulations and
|
|
mod_rewrite?</STRONG>
|
|
</A>
|
|
<P>
|
|
There is an article from
|
|
<A
|
|
HREF="mailto:rse@apache.org"
|
|
>Ralf S. Engelschall</A>
|
|
about URL-manipulations based on
|
|
<A
|
|
HREF="../mod/mod_rewrite.html"
|
|
><SAMP>mod_rewrite</SAMP></A>
|
|
in the "iX Multiuser Multitasking Magazin" issue #12/96. The
|
|
german (original) version
|
|
can be read online at
|
|
<A
|
|
HREF="http://www.heise.de/ix/artikel/9612149/"
|
|
>http://www.heise.de/ix/artikel/9612149/</A>,
|
|
the English (translated) version can be found at
|
|
<A
|
|
HREF="http://www.heise.de/ix/artikel/E/9612149/"
|
|
>http://www.heise.de/ix/artikel/E/9612149/</A>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-complexity">
|
|
<STRONG>Why is mod_rewrite so difficult to learn and seems so
|
|
complicated?</STRONG>
|
|
</A>
|
|
<P>
|
|
Hmmm... there are a lot of reasons. First, mod_rewrite itself is a powerful
|
|
module which can help you in really <STRONG>all</STRONG> aspects of URL rewriting, so
|
|
it can be no trivial module per definition. To accomplish its hard job it
|
|
uses software leverage and makes use of a powerful regular expression
|
|
library by Henry Spencer which is an integral part of Apache since its
|
|
version 1.2. And regular expressions itself can be difficult to newbies,
|
|
while providing the most flexible power to the advanced hacker.
|
|
</P>
|
|
<P>
|
|
On the other hand mod_rewrite has to work inside the Apache API environment
|
|
and needs to do some tricks to fit there. For instance the Apache API as of
|
|
1.x really was not designed for URL rewriting at the <TT>.htaccess</TT>
|
|
level of processing. Or the problem of multiple rewrites in sequence, which
|
|
is also not handled by the API per design. To provide this features
|
|
mod_rewrite has to do some special (but API compliant!) handling which leads
|
|
to difficult processing inside the Apache kernel. While the user usually
|
|
doesn't see anything of this processing, it can be difficult to find
|
|
problems when some of your RewriteRules seem not to work.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-dontwork">
|
|
<STRONG>What can I do if my RewriteRules don't work as expected?
|
|
</STRONG>
|
|
</A>
|
|
<P>
|
|
Use "<SAMP>RewriteLog somefile</SAMP>" and
|
|
"<SAMP>RewriteLogLevel 9</SAMP>" and have a precise look at the
|
|
steps the rewriting engine performs. This is really the only one and best
|
|
way to debug your rewriting configuration.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-prefixdocroot"><STRONG>Why don't some of my URLs
|
|
get prefixed with DocumentRoot when using mod_rewrite?</STRONG>
|
|
</A>
|
|
<P>
|
|
If the rule starts with <SAMP>/somedir/...</SAMP> make sure that really no
|
|
<SAMP>/somedir</SAMP> exists on the filesystem if you don't want to lead the
|
|
URL to match this directory, i.e. there must be no root directory named
|
|
<SAMP>somedir</SAMP> on the filesystem. Because if there is such a
|
|
directory, the URL will not get prefixed with DocumentRoot. This behaviour
|
|
looks ugly, but is really important for some other aspects of URL
|
|
rewriting.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-nocase">
|
|
<STRONG>How can I make all my URLs case-insensitive with mod_rewrite?
|
|
</STRONG>
|
|
</A>
|
|
<P>
|
|
You can't! The reason is: First, case translations for arbitrary length URLs
|
|
cannot be done <EM>via</EM> regex patterns and corresponding substitutions.
|
|
One need
|
|
a per-character pattern like sed/Perl <SAMP>tr|..|..|</SAMP> feature.
|
|
Second, just
|
|
making URLs always upper or lower case will not resolve the complete problem
|
|
of case-INSENSITIVE URLs, because actually the URLs had to be rewritten to
|
|
the correct case-variant residing on the filesystem because in later
|
|
processing Apache needs to access the file. And Unix filesystem is always
|
|
case-SENSITIVE.
|
|
</P>
|
|
<P>
|
|
But there is a module named <CODE>mod_speling.c</CODE> (yes, it is named
|
|
this way!) out there on the net. Try this one.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-virthost">
|
|
<STRONG> Why are RewriteRules in my VirtualHost parts ignored?
|
|
</STRONG>
|
|
</A>
|
|
<P>
|
|
Because you have to enable the engine for every virtual host explicitly due
|
|
to security concerns. Just add a "RewriteEngine on" to your
|
|
virtual host configuration parts.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="rewrite-envwhitespace">
|
|
<STRONG> How can I use strings with whitespaces in RewriteRule's ENV
|
|
flag?</STRONG>
|
|
</A>
|
|
<P>
|
|
There is only one ugly solution: You have to surround the complete flag
|
|
argument by quotation marks (<SAMP>"[E=...]"</SAMP>). Notice: The argument
|
|
to quote here is not the argument to the E-flag, it is the argument of the
|
|
Apache config file parser, i.e. the third argument of the RewriteRule here.
|
|
So you have to write <SAMP>"[E=any text with whitespaces]"</SAMP>.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="cgi-spec"><STRONG>Where can I find the "CGI
|
|
specification"?</STRONG></A>
|
|
<P>
|
|
The Common Gateway Interface (CGI) specification can be found at
|
|
the original NCSA site
|
|
<<A HREF="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html">
|
|
<SAMP>http://hoohoo.ncsa.uiuc.edu/cgi/interface.html</SAMP></A>>.
|
|
This version hasn't been updated since 1995, and there have been
|
|
some efforts to update it.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="year2000">
|
|
<STRONG>Is Apache Year 2000 compliant?</STRONG>
|
|
</A>
|
|
<P>
|
|
Yes, Apache is Year 2000 compliant.
|
|
</P>
|
|
<P>
|
|
Apache internally never stores years as two digits.
|
|
On the HTTP protocol level RFC1123-style addresses are generated
|
|
which is the only format a HTTP/1.1-compliant server should
|
|
generate. To be compatible with older applications Apache
|
|
recognizes ANSI C's <CODE>asctime()</CODE> and
|
|
RFC850-/RFC1036-style date formats, too.
|
|
The <CODE>asctime()</CODE> format uses four-digit years,
|
|
but the RFC850 and RFC1036 date formats only define a two-digit year.
|
|
If Apache sees such a date with a value less than 70 it assumes that
|
|
the century is <SAMP>20</SAMP> rather than <SAMP>19</SAMP>.
|
|
</P>
|
|
<P>
|
|
Some aspects of Apache's output may use two-digit years, such as the
|
|
automatic listing of directory contents provided by
|
|
<A
|
|
HREF="../mod/mod_autoindex.html"
|
|
><SAMP>mod_autoindex</SAMP></A>
|
|
with the
|
|
<A
|
|
HREF="../mod/mod_autoindex.html#indexoptions"
|
|
><SAMP>FancyIndexing</SAMP></A>
|
|
option enabled, but it is improper to depend upon such displays for
|
|
specific syntax. And even that issue is being addressed by the
|
|
developers; a future version of Apache should allow you to format that
|
|
display as you like.
|
|
</P>
|
|
<P>
|
|
Although Apache is Year 2000 compliant, you may still get problems
|
|
if the underlying OS has problems with dates past year 2000
|
|
(<EM>e.g.</EM>, OS calls which accept or return year numbers).
|
|
Most (UNIX) systems store dates internally as signed 32-bit integers
|
|
which contain the number of seconds since 1<SUP>st</SUP> January 1970, so
|
|
the magic boundary to worry about is the year 2038 and not 2000.
|
|
But modern operating systems shouldn't cause any trouble
|
|
at all.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
<LI><A NAME="namevhost">
|
|
<STRONG>I upgraded to Apache 1.3b and now my virtual hosts don't
|
|
work!</STRONG>
|
|
</A>
|
|
<P>
|
|
In versions of Apache prior to 1.3b2, there was a lot of confusion
|
|
regarding address-based virtual hosts and (HTTP/1.1) name-based
|
|
virtual hosts, and the rules concerning how the server processed
|
|
<SAMP><VirtualHost></SAMP> definitions were very complex and not
|
|
well documented.
|
|
</P>
|
|
<P>
|
|
Apache 1.3b2 introduced a new directive,
|
|
<A
|
|
HREF="http://www.apache.org/docs/mod/core.html#namevirtualhost"
|
|
><SAMP>NameVirtualHost</SAMP></A>,
|
|
which simplifies the rules quite a bit. However, changing the rules
|
|
like this means that your existing name-based
|
|
<SAMP><VirtualHost></SAMP> containers probably won't work
|
|
correctly immediately following the upgrade.
|
|
</P>
|
|
<P>
|
|
To correct this problem, add the following line to the beginning of
|
|
your server configuration file, before defining any virtual hosts:
|
|
</P>
|
|
<DL>
|
|
<DD><CODE>NameVirtualHost <EM>n.n.n.n</EM></CODE>
|
|
</DD>
|
|
</DL>
|
|
<P>
|
|
Replace the "<SAMP>n.n.n.n</SAMP>" with the IP address to
|
|
which the name-based virtual host names resolve; if you have multiple
|
|
name-based hosts on multiple addresses, repeat the directive for each
|
|
address.
|
|
</P>
|
|
<P>
|
|
Make sure that your name-based <SAMP><VirtualHost></SAMP> blocks
|
|
contain <SAMP>ServerName</SAMP> and possibly <SAMP>ServerAlias</SAMP>
|
|
directives so Apache can be sure to tell them apart correctly.
|
|
</P>
|
|
<P>
|
|
Please see the
|
|
<A HREF="http://www.apache.org/docs/vhosts/">Apache
|
|
Virtual Host documentation</A> for further details about configuration.
|
|
</P>
|
|
<HR>
|
|
</LI>
|
|
|
|
<!-- Don't forget to add HR tags at the end of each list item.. -->
|
|
|
|
</OL>
|
|
<!--#include virtual="footer.html" -->
|
|
</BODY>
|
|
</HTML>
|