Dear Alex.

Thanks for the tip. Please check full log at  https://pastebin.com/JmdS6Sw5 
<https://pastebin.com/JmdS6Sw5> .

In this attempt, I tried to visit google. In this case lan dns could not 
provide a correct dns reply, but provided a No Such Domain reply instead. 


> On Jan 13, 2026, at 9:48 AM, Alex Rousskov <[email protected]> 
> wrote:
> 
> On 2026-01-12 20:22, Archer wrote:
> 
>> 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
> 
> 
> FWIW, if I have access to a full debugging log collected while reproducing 
> the problem, I may be able to tell you what causes DNS lookups in your 
> specific environment. I discourage Squid admins from studying debugging logs 
> because they are meant for Squid developers and can be very misleading.
> 
> https://wiki.squid-cache.org/SquidFaq/BugReporting#debugging-a-single-transaction
> 
> Without looking at the logs, and without investing a lot of time in trying to 
> reproduce the problem locally based on the partial information you have 
> shared, I can only offer guesses, and I have done that already.
> 
> Alex.
> 
> 
>> 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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