[squid-users] peer-select.cc, cache_peer and dns queries

[Archer]

Thank you. I picked up this part of log as  evidence that Squid does conduct DNS lookups AFTER a peer connection is selected( log ommited). In the configuration, a cache peer (parent proxy) for specified domains presents.




And the relative part of config is already provided in some other thread of this post. TY

















Archer


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----The following is the content of the forwarded email----
From：Alex Rousskov 
To：squid-users 
Date：2026-01-13 04:02:09
Subject：Re: [squid-users] peer-select.cc, cache_peer and dns queries

On 2026-01-09 17:19, archer wrote:

> cache_peer a.b.c.d parent ... name=NodeNG
> always_direct extranet_whitelist
> never_direct extranet


> I observed peer-select.cc still conducting DNS 
> lookups on an extranet domain , which is a purely domain-based ACL. e.g.
> 
> peer_select.cc(833) selectSomeParent: CONNECT www.example.com
> ...
> peer_select.cc(460) resolveSelected: Find IP 
> destination for: www.example.com:443 via a.b.c.d

The above debugging log snippet is unrelated to ACLs checking/code.

Squid says that it needs to resolve a.b.c.d to connect to a peer at that 
a.b.c.d address. If a.b.c.d is alerady an IP address, then that 
resolution is going to be a no-op -- no actual DNS queries will be sent.

I do not know what triggers other DNS queries in your case. If I have to 
guess, I would guess that peer selection algorithm finds multiple ways 
to satisfy that CONNECT-to-X request and some of those ways include a 
direct connection to X, triggering X resolution.


> So, what can I do to have extranet DNS handled by the parent proxy, 
> while leaving the remainder to the child proxy, with a domain list ?


> Squid Cache: Version 5.7

FWIW, the above version is not supported by the Squid Project.

Alex.

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