How to get proxy.pac or wpad.pad to failover

internet explorerPROXY

What happens when the hosting web or share is unavailable? IE defaults to no proxy and goes direct(ly past my two proxy servers). I'm trying to make the proxy configuration redundant, so if one server hosting proxy.pac or wpad.pad is unavailable, another server takes its place. Would I need DNS to have two WPAD A Records, pointing to what? Thanks. I'm just trying to eliminate IE's single point of failure.

Best Answer

You should be able to include a failover in the wpad file itself. This is the wpad file we use where I work:

function FindProxyForURL(url, host) {

// If URL has no dots in host name, send traffic direct.
    if (isPlainHostName(host))
        return "DIRECT";

// If specific URL needs to bypass proxy, send traffic direct.
    if (shExpMatch(url,"*internal.mydomain.ac.uk*"))                  
        return "DIRECT";

// All other traffic uses below proxies, in fail-over order.
    return "PROXY proxy1.internal.mydomain.ac.uk:8080; PROXY proxy2.internal.mydomain.ac.uk:8080";

}

Does this not work for you?

Related Solutions

Cannot get proxy.pac file to get browsers to go DIRECT for localhost

I've not tried it but according to the sun.com docco, the IsInNet function takes a host, not an IP as the first param.

so I think that this:

if (isInNet(resolved_ip, "172.22.145.0",  "255.255.255.0") ||
        isInNet(resolved_ip, "192.168.1.0", "255.255.255.0") ||
        isInNet(resolved_ip, "127.0.0.1", "255.255.255.255"))
return "DIRECT";

should be changed to this:

if (isInNet(host, "172.22.145.0",  "255.255.255.0") ||
        isInNet(host, "192.168.1.0", "255.255.255.0") ||
        isInNet(host, "127.0.0.1", "255.255.255.255"))
return "DIRECT";

ShExpMatch and Internet Explorer 6 in a proxy.pac

Here's a slightly modified WPAD.DAT I'm using at a Customer site. It's working fine on IE6, unmodified... (because they won't give me the go-ahead to upgrade to IE8). The only modifications I put in were to obscure the Customer's domain names.

function FindProxyForURL(url, host) {

  if ( isPlainHostName(host) ) { return "DIRECT"; }

  if ( shExpMatch(url, "https:*") ) { return "DIRECT"; }

  if ( shExpMatch(url,"http://*.customer.domain.com")) { return "DIRECT"; }

  if ( isInNet(host,"127.0.0.1", "255.255.255.255") ) { return "DIRECT"; }

  if ( isInNet(host,"10.35.0.0", "255.255.0.0") ) { return "DIRECT"; }

  if ( isInNet(host,"192.168.0.0", "255.255.0.0") ) { return "DIRECT"; }

  return "PROXY proxy.customer.domain.com:8080";
}

The only difference that I see is that you're not matching "http:" at the beginning, but that shouldn't matter.

You're not supposed to do it, but you can put alert() statements in and IE6 will display them. You may be able to get some traction in debugging by doing that.

Best Answer

Related Solutions

Cannot get proxy.pac file to get browsers to go DIRECT for localhost

ShExpMatch and Internet Explorer 6 in a proxy.pac

Related Topic