Re: AW: [squid-users] Does any cache in a proxy chain but the last one need to resolve URLs?

On 29/04/11 01:56, Jannis Kafkoulas wrote:
> Of cource Eliezer, thanks a lot!
>
>
> Yes, of course, I mean dns lookup by resolve.
>
> (It has been set up by an external company)
>
> The chain is very simple, just one after the other:
>
> clients (FF) ---> Squid1 (LAN) ----> Squid2 (somewhere in between) ---> Squid3
> (at the Internet)
>
> This chain is being used by the users when accessing the Internet.
> It's the same behaviour for any possible URL.
> I took just a rare one so I could find it easily in the tcpdump output.
> I just checked the squid1 and squid 3 (squid 2 same as squid1).
> Squid one contacts the internal dns server which forwards to the root servers.
> But the dns answer to the query is not given to the next proxy in the chain, so
> it's then useless.
> The squid 3 accesses the dns root servers directly and then it forwards the http
> request to the final server.
>
> The problem might be that the squid 1 also is being used for internal "direct
> access", i.e without a parent.
>
> My question is now, is it possible for the squid to decide when to use a dns
> lookup?

Yes. DNS "should" not be needed until the stage of setting up the DIRECT
TCP connection. It sounds like squid1 has some ACLs or such which are
testing DNS things about the request. Find and avoid those and DNS will
go away on the chained requests.

Amos

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