Proxy by dhcpd that don't work ?

Alex Sharaz A.Sharaz at
Tue Feb 5 11:08:40 UTC 2008

I'm having problems with this as well. Up till Friday I had

option wpad-curl "\n";

Which seemed  to work for 99.9% of IE clients and never worked for
firefox/Mozilla clients.

On Friday I changed the string termination to be \000 to see if we'd
sort out the last .1% of users. Seems to have been a mistake cos our
helpdesk had quite a few calls from users saying that their internet
access had stopped.

Going back to the \n version seems to have fixed things.

In terms of accessing, What i've got is a foundry
networks serveriron hardware load balancer platform with 3 real servers
sitting behind them. Wpad.hull... is set up as a virtual host on the
real servers and the serveriron load balances requests to the 3 real
servers. As a catch all, there is a default web server running on each
of the 3 real servers in case someone tries to get the wpad.dat by

What i've found is that all the Mozilla/firefox traffic seems to go to
the default server and not the wpad.hull .. virtual host.

There's also a lot of other things out there that seem to go for the
ipaddress/wpad.dat url as well.

In general once you've applied all the service packs to a windoze
machine this "just work" but  we do have some systems that just refuse
point blank to work with auto detect proxy settings.


-----Original Message-----
From: dhcp-users-bounce at [mailto:dhcp-users-bounce at] On
Behalf Of Glenn Satchell
Sent: 05 February 2008 10:22
To: dhcp-users at
Subject: Re: Proxy by dhcpd that don't work ?

If you load the proxy url in your browser do you get the file?

Some versions of operating systems have a bug where they drop the last
char of the url. So it tries to get
and gets an error which should be in your web server error logs if it
is a problem.

In a post the other day I showed a null on the end of the wpad-url, eg

option wpad-url "\000";

which has worked well for me and gets around the truncation.

Does the proxy.dat file work if you specify that url as a manual proxy 
configuration in the browser config? If there is a syntax error, then
browser may refuse to load it.


>Date: Tue, 05 Feb 2008 10:26:12 +0100
>From: Phibee Network Operation Center <noc at>
>To: dhcp-users at
>Subject: Proxy by dhcpd that don't work ?
>i have put:
>ddns-update-style none;
>default-lease-time 3600;
>max-lease-time 86400;
>option wpad-url code 252 = text;
>subnet netmask {
>       option domain-name "";
>       option domain-name-servers;
>       option subnet-mask;
>       option broadcast-address;
>       option routers;
>       option ntp-servers;
>       option wpad-url "";
>       pool {
>               range;
>       }
>and in proxy.dat:
>function FindProxyForURL(url, host)
>   if( shExpMatch(url, "!https:*") || isPlainHostName(host) || \
>       dnsDomainIs(host, "") || dnsDomainIs(host, 
>"") )
>   {
>       return "DIRECT";
>   } else {
>       return "PROXY; DIRECT";
>   }
>and i don't understand, that's don't work  ! the computer get the IP
>the proxy don't change and  i don't see into logs a http access to
>where is my error ?
>Thanks bye
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