diff --git a/Makefile b/Makefile
index 064c860d..9dd77981 100644
--- a/Makefile
+++ b/Makefile
@@ -83,6 +83,7 @@ LIB_SOURCES =	src/libhttp.c						\
 		src/httplib_initialize_ssl.c				\
 		src/httplib_is_not_modified.c				\
 		src/httplib_is_valid_http_method.c			\
+		src/httplib_is_valid_port.c				\
 		src/httplib_is_websocket_protocol.c			\
 		src/httplib_load_dll.c					\
 		src/httplib_lock_unlock_connection.c			\
diff --git a/src/httplib_is_valid_port.c b/src/httplib_is_valid_port.c
new file mode 100644
index 00000000..3a492db2
--- /dev/null
+++ b/src/httplib_is_valid_port.c
@@ -0,0 +1,35 @@
+/* 
+ * Copyright (c) 2016 Lammert Bies
+ * Copyright (c) 2013-2016 the Civetweb developers
+ * Copyright (c) 2004-2013 Sergey Lyubka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+
+#include "libhttp-private.h"
+
+
+
+int XX_httplib_is_valid_port(unsigned long port) {
+
+	return (port < 0xffff);
+
+}  /* XX_httplib_is_valid_port */
diff --git a/src/libhttp.c b/src/libhttp.c
index 3817bb92..a9443833 100644
--- a/src/libhttp.c
+++ b/src/libhttp.c
@@ -4314,10 +4314,3 @@ int mg_modify_passwords_file(const char *fname, const char *domain, const char *
 
 	return 1;
 }
-
-
-int XX_httplib_is_valid_port(unsigned long port) {
-
-	return (port < 0xffff);
-
-}  /* XX_httplib_is_valid_port */