Re: [squid-users] Unwanted DNS queries

On 25/09/2013 8:25 p.m., T Ls wrote:
> Hi,
>
> Am 24.9.2013 16:25, schrieb Amos Jeffries:
>> ...Perhase a "debug_options ALL,1 11,6 78,6" trace would be more
>> informative.
>
> To get an usefull example in the logfiles I requestet
> http://www.uni-leipzig.de, I found the following in cache.log:
>
> ...

This start is some other transaction ending
> 2013/09/25 09:08:47.988| persistentConnStatus: FD 17 eof=0
> 2013/09/25 09:08:47.988| persistentConnStatus: content_length=4
> 2013/09/25 09:08:47.988| persistentConnStatus: clen=4
> 2013/09/25 09:08:47.988| persistentConnStatus: body_bytes_read=4
> content_length=4
> 2013/09/25 09:08:47.988| processReplyBody: COMPLETE_PERSISTENT_MSG
> 2013/09/25 09:08:47.988| Server.cc(169) serverComplete: serverComplete
> 0x7fa5b432dc48
> 2013/09/25 09:08:47.988| Server.cc(194) serverComplete2:
> serverComplete2 0x7fa5b432dc48
> 2013/09/25 09:08:47.988| Server.cc(234) completeForwarding: completing
> forwarding for 0x7fa5b4019728*2
> 2013/09/25 09:08:47.988| Server.cc(225) quitIfAllDone: transaction done
> 2013/09/25 09:08:47.988| Server.cc(556) cleanAdaptation: cleaning
> ICAP; ACL: 0
> 2013/09/25 09:08:47.988| http.cc(163) ~HttpStateData: HttpStateData
> 0x7fa5b432dc48 destroyed; FD -1
> 2013/09/25 09:08:47.988| leaving HttpStateData::readReply(FD 17,
> data=0x7fa5b432dc48, size=131, buf=0x7fa5b4332680)

This appears to be the start of a FwdState::dispatch() event which
handles the results from peer selection and kicks off the HTTP request
generate+send ativities.
Can you add debug options 17,5 38,6 to these and confirm that in a new
trace please?

> 2013/09/25 09:08:48.929| idnsALookup: buf is 36 bytes for
> www.uni-leipzig.de, id = 0x44dd

Assuming I'm right about that ...

  that would make this the netdbPingSite() probe to test how far away
the domain is. Squid looks up the host IPs then pings them all in
various ways to measure latency and assist peer selection on later traffic.
It is not clear why that is using the URL hostname instead of the peer's
hostname. Or why it is even being run at this point in the forwarding
process. It would seem to have been more relevant a stage or two earlier
while determining where to route the request.

> 2013/09/25 09:08:48.929| httpStart: "GET http://www.uni-leipzig.de/"

If it was important to suppress these lookups you could build your Squid
with --disable-icmp or comment out the particular call to
netdbPingSite() in FwdState::dispatch() method of src/forward.cc.

Amos
Received on Wed Sep 25 2013 - 14:00:28 MDT