RE: [squid-users] more dns problems

From: Proescholdt, timo <>
Date: Fri, 23 Nov 2001 13:16:32 +0100

Hi Henrik,

thanks for your email,

I think it´s internal DNS as i did not change such a setting.
Can you tell me about the differences between the internal
and external setting?

What i noticed playing around with tcpdump und snoop
ist, that once i start a request from by browser, a
dns request from squid to server 1 ( which is down ) is
made, after 4 minutes a second request is send to server 2
( which is online ) and then the page is loaded, for the
next requests ( and there are many for one page )
, squid sends the queries to server1 und server2 .
So once the name is resolved, the following queries
are sent to both of the servers.
When i now try to get annother url, the same thing
happens, but with not so huge timeouts. (maybe 10 seconds).
The next try has again that enormous timeout.

What i notice again and again, is that for 1 (one ) Page,
depending on the number of ( pictures , html pages and so on)
on the page between 10 - an 30 dns requests for the record
are sent from the cache to the nameserver.
Is this normal behaviour ? This happens for all pages
i try, so i can exclude that ttl´s are set to 0.
Unfortunately i have no dig here. But testing the
ttls for the record i tested, from otherwhere showed
that ttls are set to a normal value. So it is not that!

Maybee these two problems belong together?

A cannot confirm that reverse lookups are made, but even
if, the secondary nameserver is secondary for the
4[0,1] zones as well and can
answer PTR queries. ( i tested ).

maybe it is a solution to install a caching only nameserver,
hwo handels the reloving transparently for the squid?

thanks again for your help

>Have you compiled Squid with internal or external DNS?
>(default is internal)

>If internal, then what TTL is your DNS server returning for these

> dig requested.servername @your.dns.server

>If external, then what TTL's have you configured for DNS lookups in

>Also, what is the lookups Squid are actually trying to perform? Could
it be
>that Squid is trying to perform a reverse lookup of the client IP
>and your DNS does not know about the client networks?

>A "tcpdump port 53" should tell what kind of lookups are being

>Henrik Nordström
>Squid Hacker

On Wednesday 21 November 2001 21.39, Proescholdt, timo wrote:

> It seems that squid is making a dnslookup for every item (picture,
> html-page) that it is trying
> to load, and allways trys the nameserver that is configured first in
> /etc/resolv.conf
> and after the timeout, tries the second one.

> Should not squid cache these lookups somewhere? ( that is
> what my
> last mail was about, too).

MARA Systems AB
Giving you basic free Squid support
Priority support or Squid enhancements available on request
Received on Fri Nov 23 2001 - 05:27:23 MST

This archive was generated by hypermail pre-2.1.9 : Tue Dec 09 2003 - 17:04:28 MST