diff -uNr squid-3.0.DEVEL-20030601/src/cf.data.pre squid-3.0.DEVEL-20030601.new/src/cf.data.pre
--- squid-3.0.DEVEL-20030601/src/cf.data.pre	2003-05-30 01:54:07.000000000 +1000
+++ squid-3.0.DEVEL-20030601.new/src/cf.data.pre	2003-06-02 22:16:38.000000000 +1000
@@ -2881,8 +2881,13 @@
 	and put them into the configured errors/ directory.
 
 	Alternatively you can specify an error URL. The browsers will then
-	get redirected (302) to the specified URL. %s in the redirection
-	URL will be replaced by the requested URL.
+	get redirected (302) to the specified URL. Placeholders such as %U
+	can be used in the error URL to include extra information.
+	
+	See the Squid FAQ section on Customizable Error Messages
+	(http://www.squid-cache.org/Doc/FAQ/FAQ-19.html#custom-err-msgs)
+	for more information on placeholders that can be used in ERR_ pages
+	and error URLs.
 
 	Alternatively you can tell Squid to reset the TCP connection
 	by specifying TCP_RESET.
diff -uNr squid-3.0.DEVEL-20030601/src/errorpage.cc squid-3.0.DEVEL-20030601.new/src/errorpage.cc
--- squid-3.0.DEVEL-20030601/src/errorpage.cc	2003-03-10 14:56:38.000000000 +1000
+++ squid-3.0.DEVEL-20030601.new/src/errorpage.cc	2003-06-03 23:07:25.000000000 +1000
@@ -101,9 +101,9 @@
 static const char *errorFindHardText(err_type type);
 static ErrorDynamicPageInfo *errorDynamicPageInfoCreate(int id, const char *page_name);
 static void errorDynamicPageInfoDestroy(ErrorDynamicPageInfo * info);
-static MemBuf errorBuildContent(ErrorState * err);
+static MemBuf errorBuildContent(ErrorState * err, int buildUrl = 0);
 static int errorDump(ErrorState * err, MemBuf * mb);
-static const char *errorConvert(char token, ErrorState * err);
+static const char *errorConvert(char token, ErrorState * err, int do_quote = 1);
 static CWCB errorSendComplete;
 
 
@@ -590,12 +590,11 @@
  */
 
 static const char *
-errorConvert(char token, ErrorState * err)
+errorConvert(char token, ErrorState * err, int do_quote)
 {
     request_t *r = err->request;
     static MemBuf mb = MemBufNULL;
     const char *p = NULL;	/* takes priority over mb if set */
-    int do_quote = 1;
 
     memBufReset(&mb);
 
@@ -826,10 +825,13 @@
 
     if (strchr(name, ':')) {
         /* Redirection */
-        char *quoted_url = rfc1738_escape_part(errorConvert('u', err));
+        MemBuf redirectUrl;
+        /* replace format strings in the URL with rfc1738 escaped data */
+        redirectUrl = errorBuildContent(err, true);
         httpReplySetHeaders(rep, version, HTTP_MOVED_TEMPORARILY, NULL, "text/html", 0, 0, squid_curtime);
-        httpHeaderPutStrf(&rep->header, HDR_LOCATION, name, quoted_url);
+        httpHeaderPutStr(&rep->header, HDR_LOCATION, redirectUrl.buf);
         httpHeaderPutStrf(&rep->header, HDR_X_SQUID_ERROR, "%d %s\n", err->httpStatus, "Access Denied");
+        memBufClean(&redirectUrl);
     } else {
         MemBuf content = errorBuildContent(err);
         httpReplySetHeaders(rep, version, err->httpStatus, NULL, "text/html", content.size, 0, squid_curtime);
@@ -851,7 +853,7 @@
 }
 
 static MemBuf
-errorBuildContent(ErrorState * err)
+errorBuildContent(ErrorState * err, int buildUrl)
 {
     MemBuf content;
     const char *m;
@@ -860,14 +862,14 @@
     assert(err != NULL);
     assert(err->page_id > ERR_NONE && err->page_id < error_page_count);
     memBufDefInit(&content);
-    m = error_text[err->page_id];
+    m = buildUrl ? errorPageName(err->page_id) : error_text[err->page_id]; 
     assert(m);
 
     while ((p = strchr(m, '%'))) {
-        memBufAppend(&content, m, p - m);	/* copy */
-        t = errorConvert(*++p, err);	/* convert */
-        memBufPrintf(&content, "%s", t);	/* copy */
-        m = p + 1;		/* advance */
+        memBufAppend(&content, m, p - m);		/* copy */
+        t = errorConvert(*++p, err, buildUrl ? 0 : 1);	/* convert */
+        memBufPrintf(&content, "%s", buildUrl ? rfc1738_escape_part(t) : t);
+        m = p + 1;					/* advance */
     }
 
     if (*m)