Re: [squid-users] IE5/Win2k/WPAD not working[Scanned]

On Mon, 15 Sep 2003, Diego Rivera wrote:

> Hello all!!
>
> I've followed every article and howto on the subject and still can't get
> it to work!!
>
> Basically: from the Win2k box's IE5 I can open "http://wpad/wpad.dat"
> perfectly. Even "http://wpad.mydomain.com/wpad.dat", etc. These in
> reality point to an apache server.
>
> [...]
>
> The strange thing is after doing some packet sniffs, the win2k box isn't
> even doing a DNS search for "wpad", "wpad.mydomain.com" (etc.), even
> after an "ipconfig /flushdns" (to flush DNS caches). No local DNS is
> running on the box.

I had configured an array of squid proxies that were crudely balanced by
hashing the requested URL. I noticed that Win2K and other systems running
IE6 did not switch between the proxies. Searching Microsoft's Knowledge
Base that Win2K and other systems running IE6 cache the proxy to use for
the domain name associated with each URL. A registry modification is needed
to disable this behaviour. It appears that as long as the system stays in
the same domain, it will not attempt to retrieve wpad.dat once it has cached
the proxy data until the Web proxy auto detect flag is manualy toggled.

If you are using DHCP and option 252 is defined, the DNS method of locating
the proxy will not be used. It will use the URL returned in the DHCPINFORM
packet.

Hopefully my memory isn't too faulty. :)

Merton Campbell Crockett

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