diff -ur apache.orig/htdocs/manual/mod/mod_proxy.html apache_1.3.24/htdocs/manual/mod/mod_proxy.html
--- htdocs/manual/mod/mod_proxy.html	Thu Mar 21 17:28:49 2002
+++ htdocs/manual/mod/mod_proxy.html	Fri May 31 18:57:58 2002
@@ -61,6 +61,8 @@
 
       <li><a href="#proxypassreverse">ProxyPassReverse</a></li>
 
+      <li><a href="#proxypreservehost">ProxyPreserveHost</a></li>
+
       <li><a href="#proxyblock">ProxyBlock</a></li>
 
       <li><a href="#allowconnect">AllowCONNECT</a></li>
@@ -453,6 +455,31 @@
     href="mod_rewrite.html#RewriteRule"><tt>mod_rewrite</tt></a>
     because its doesn't depend on a corresponding
     <samp>ProxyPass</samp> directive.</p>
+    <hr />
+
+    <h2><a id="proxypreservehost"
+    name="proxypreservehost">ProxyPreserveHost</a> directive</h2>
+    <a href="directive-dict.html#Syntax"
+    rel="Help"><strong>Syntax:</strong></a> ProxyPreserveHost
+    on|off<br />
+     <a href="directive-dict.html#Default"
+    rel="Help"><strong>Default:</strong></a> <code>ProxyPreserveHost Off</code><br />
+     <a href="directive-dict.html#Context"
+    rel="Help"><strong>Context:</strong></a> server config, virtual
+    host<br />
+     <a href="directive-dict.html#Override"
+    rel="Help"><strong>Override:</strong></a> <em>Not
+    applicable</em><br />
+     <a href="directive-dict.html#Status"
+    rel="Help"><strong>Status:</strong></a> Base<br />
+     <a href="directive-dict.html#Module"
+    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
+     <a href="directive-dict.html#Compatibility"
+    rel="Help"><strong>Compatibility:</strong></a> ProxyPassReverse
+    is only available in Apache 1.3.25 and later.
+
+    <p>This directive tells Apache to preserve the <tt>Host</tt>
+    header from incoming requests on outgoing proxy requests.</p>
     <hr />
 
     <h2><a id="allowconnect" name="allowconnect">AllowCONNECT</a>
diff -ur apache.orig/src/modules/proxy/mod_proxy.c apache_1.3.24/src/modules/proxy/mod_proxy.c
--- src/modules/proxy/mod_proxy.c	Fri May 31 18:56:10 2002
+++ src/modules/proxy/mod_proxy.c	Fri May 31 18:57:58 2002
@@ -436,6 +436,8 @@
     ps->viaopt_set = 0;         /* 0 means default */
     ps->req = 0;
     ps->req_set = 0;
+    ps->phh = 0;
+    ps->phh_set = 0;
     ps->recv_buffer_size = 0;   /* this default was left unset for some
                                  * reason */
     ps->recv_buffer_size_set = 0;
@@ -483,6 +485,7 @@
     ps->domain = (overrides->domain == NULL) ? base->domain : overrides->domain;
     ps->viaopt = (overrides->viaopt_set == 0) ? base->viaopt : overrides->viaopt;
     ps->req = (overrides->req_set == 0) ? base->req : overrides->req;
+    ps->phh = (overrides->phh_set == 0) ? base->phh : overrides->phh;
     ps->recv_buffer_size = (overrides->recv_buffer_size_set == 0) ? base->recv_buffer_size : overrides->recv_buffer_size;
     ps->io_buffer_size = (overrides->io_buffer_size_set == 0) ? base->io_buffer_size : overrides->io_buffer_size;
 
@@ -703,6 +706,19 @@
 
 
 static const char *
+     set_proxy_preserve_host(cmd_parms *parms, void *dummy, int flag)
+{
+    proxy_server_conf *psf =
+    ap_get_module_config(parms->server->module_config, &proxy_module);
+
+    psf->phh = flag;
+    psf->phh_set = 1;
+
+    return NULL;
+}
+
+
+static const char *
      set_cache_size(cmd_parms *parms, char *struct_ptr, char *arg)
 {
     proxy_server_conf *psf =
@@ -936,6 +952,8 @@
     "a virtual path and a URL"},
     {"ProxyPassReverse", add_pass_reverse, NULL, RSRC_CONF, TAKE2,
     "a virtual path and a URL for reverse proxy behaviour"},
+    {"ProxyPreserveHost", set_proxy_preserve_host, NULL, RSRC_CONF, FLAG,
+    "on if the original Host: header should be preserved"},
     {"ProxyBlock", set_proxy_exclude, NULL, RSRC_CONF, ITERATE,
     "A list of names, hosts or domains to which the proxy will not connect"},
     {"ProxyReceiveBufferSize", set_recv_buffer_size, NULL, RSRC_CONF, TAKE1,
diff -ur apache.orig/src/modules/proxy/mod_proxy.h apache_1.3.24/src/modules/proxy/mod_proxy.h
--- src/modules/proxy/mod_proxy.h	Fri May 31 18:56:10 2002
+++ src/modules/proxy/mod_proxy.h	Fri May 31 18:57:58 2002
@@ -192,6 +192,8 @@
     char *domain;               /* domain name to use in absence of a domain name in the request */
     int req;                    /* true if proxy requests are enabled */
     char req_set;
+    int phh;		/* true if we want to preserve the host header */
+    char phh_set;
     enum {
       via_off,
       via_on,
diff -ur apache.orig/src/modules/proxy/proxy_http.c apache_1.3.24/src/modules/proxy/proxy_http.c
--- src/modules/proxy/proxy_http.c	Fri May 31 18:56:10 2002
+++ src/modules/proxy/proxy_http.c	Fri May 31 18:57:58 2002
@@ -312,7 +312,7 @@
 		    AP_HOOK_SIG6(int,ptr,ptr,ptr,int,ptr), 
 		    AP_HOOK_DECLINE(DECLINED),
 		    &rc, r, f, desthost, destport, destportstr);
-        if (rc == DECLINED) {
+        if (rc == DECLINED && !conf->phh) {
 	    if (destportstr != NULL && destport != DEFAULT_HTTP_PORT)
 		ap_bvputs(f, "Host: ", desthost, ":", destportstr, CRLF, NULL);
 	    else
@@ -320,11 +320,14 @@
         }
     }
 #else /* EAPI */
-    /* Send Host: now, adding it to req_hdrs wouldn't be much better */
-    if (destportstr != NULL && destport != DEFAULT_HTTP_PORT)
-        ap_bvputs(f, "Host: ", desthost, ":", destportstr, CRLF, NULL);
-    else
-        ap_bvputs(f, "Host: ", desthost, CRLF, NULL);
+     /* Don't send Host: if we are preserving it */
+     if (!conf->phh) {
+       /* Send Host: now, adding it to req_hdrs wouldn't be much better */
+       if (destportstr != NULL && destport != DEFAULT_HTTP_PORT)
+ 	ap_bvputs(f, "Host: ", desthost, ":", destportstr, CRLF, NULL);
+       else
+ 	ap_bvputs(f, "Host: ", desthost, CRLF, NULL);
+     }
 #endif /* EAPI */
 
     if (conf->viaopt == via_block) {
@@ -363,7 +366,6 @@
          * Clear out hop-by-hop request headers not to send: RFC2616 13.5.1
          * says we should strip these headers:
          */
-            || !strcasecmp(reqhdrs_elts[i].key, "Host") /* Already sent */
             || !strcasecmp(reqhdrs_elts[i].key, "Keep-Alive")
             || !strcasecmp(reqhdrs_elts[i].key, "TE")
             || !strcasecmp(reqhdrs_elts[i].key, "Trailer")
@@ -380,6 +382,9 @@
          * was authenticated or not.
          */
             || !strcasecmp(reqhdrs_elts[i].key, "Proxy-Authorization"))
+	  continue;
+	/* Don't drop Host if we are preserving it */
+        if (!conf->phh  &&  !strcasecmp(reqhdrs_elts[i].key, "Host"))
             continue;
         ap_bvputs(f, reqhdrs_elts[i].key, ": ", reqhdrs_elts[i].val, CRLF, NULL);
     }