diff -Nur ../squid-2.4.STABLE6.dist/acconfig.h ./acconfig.h
--- ../squid-2.4.STABLE6.dist/acconfig.h	Mon Jan  1 23:36:54 2001
+++ ./acconfig.h	Mon Aug 26 22:13:11 2002
@@ -290,3 +290,9 @@
  * Enable support for Transparent Proxy on Linux 2.4 systems
  */
 #undef LINUX_NETFILTER
+
+/*
+ * Enable IP Authentication Hack
+ */
+#undef IP_AUTH_HACK
+
diff -Nur ../squid-2.4.STABLE6.dist/configure ./configure
--- ../squid-2.4.STABLE6.dist/configure	Thu Nov 29 00:56:25 2001
+++ ./configure	Mon Aug 26 22:25:14 2002
@@ -147,6 +147,8 @@
   --disable-unlinkd       Do not use unlinkd"
 ac_help="$ac_help
   --enable-stacktraces    Enable automatic call backtrace on fatal errors"
+ac_help="$ac_help
+  --enable-ip_auth	  This option enables the IP Authentication Hack."
 
 # Initialize some variables set by options.
 # The variables have the same names as the options, with
@@ -1800,6 +1802,21 @@
     echo "Enabling automatic stack backtraces on fatal errors"
     cat >> confdefs.h <<\EOF
 #define PRINT_STACK_TRACE 1
+EOF
+
+  fi
+
+fi
+
+
+
+# Check whether --enable-ip_auth or --disable-ip_auth was given.
+if test "${enable_ip_auth+set}" = set; then
+  enableval="$enable_ip_auth"
+   if test "$enableval" = "yes" ; then
+    echo "Enable IP_AUTH HACK"
+    cat >> confdefs.h <<\EOF
+#define IP_AUTH_HACK 1
 EOF
 
   fi
diff -Nur ../squid-2.4.STABLE6.dist/configure.in ./configure.in
--- ../squid-2.4.STABLE6.dist/configure.in	Mon Aug 26 22:01:33 2002
+++ ./configure.in	Mon Aug 26 22:10:21 2002
@@ -737,6 +737,15 @@
   fi
 ])
 
+
+AC_ARG_ENABLE(ip_auth,
+[  --enable-ip_auth       Enable IP Authentication Hack],
+[ if test "$enableval" = "yes" ; then
+    echo "Enable IP_AUTH HACK"
+    AC_DEFINE(IP_AUTH_HACK)
+  fi
+])
+
 # Force some compilers to use ANSI features
 #
 case "$host" in
diff -Nur ../squid-2.4.STABLE6.dist/include/autoconf.h.in ./include/autoconf.h.in
--- ../squid-2.4.STABLE6.dist/include/autoconf.h.in	Mon Aug 26 22:01:33 2002
+++ ./include/autoconf.h.in	Mon Aug 26 22:10:21 2002
@@ -301,6 +301,11 @@
  */
 #undef LINUX_NETFILTER
 
+/*
+ * Enable IP Authentication Hack
+ */
+#undef IP_AUTH_HACK
+
 /* The number of bytes in a int.  */
 #undef SIZEOF_INT
 
diff -Nur ../squid-2.4.STABLE6.dist/src/acl.c ./src/acl.c
--- ../squid-2.4.STABLE6.dist/src/acl.c	Tue Aug 21 07:55:47 2001
+++ ./src/acl.c	Mon Aug 26 22:10:21 2002
@@ -1095,7 +1095,14 @@
 
     if (!aclDecodeProxyAuth(proxy_auth, &user, &password, login_buf, sizeof(login_buf)))
 	/* No or invalid Proxy-Auth header */
+#ifdef IP_AUTH_HACK
+        /* Set username to ip address */
+	user = inet_ntoa(checklist->src_addr);
+	password = "IP_AUTH"; 
+	debug(28, 4) ("aclMatchProxyAuth: IP_AUTH: trying '%s'\n", user);
+#else
 	return -2;
+#endif
 
     debug(28, 5) ("aclMatchProxyAuth: checking user '%s'\n", user);
 
@@ -1217,6 +1224,16 @@
     }
     ok = aclDecodeProxyAuth(proxy_auth, &user, &password, login_buf,
 	sizeof(login_buf));
+
+#ifdef IP_AUTH_HACK
+    /* try IP_AUTH */
+    if (!ok) {
+	user = inet_ntoa(checklist->src_addr);
+	password = "IP_AUTH"; 
+	ok = 1;
+     }
+#endif
+
     /*
      * if aclDecodeProxyAuth() fails, the same call should have failed
      * in aclMatchProxyAuth, and we should never get this far.
diff -Nur ../squid-2.4.STABLE6.dist/src/client_side.c ./src/client_side.c
--- ../squid-2.4.STABLE6.dist/src/client_side.c	Mon Aug 26 22:01:34 2002
+++ ./src/client_side.c	Mon Aug 26 22:10:22 2002
@@ -245,8 +245,14 @@
 	    null_request_flags);
 	if (answer == ACCESS_REQ_PROXY_AUTH || aclIsProxyAuth(AclMatchedName)) {
 	    if (!http->flags.accel) {
+#ifdef IP_AUTH_HACK
+		/* Do not let the browser ask for a password */
+		debug(33, 7)("IP_AUTH_HACK: sending HTTP_FORBIDDEN\n");
+		status = HTTP_FORBIDDEN;
+#else
 		/* Proxy authorisation needed */
 		status = HTTP_PROXY_AUTHENTICATION_REQUIRED;
+#endif
 	    } else {
 		/* WWW authorisation needed */
 		status = HTTP_UNAUTHORIZED;