Re: [squid-users] DNS double query

> On Tue, 13 Apr 2004, dtom wrote:
>
> > OK.Here is snoop output with timing details.
> >
> > # snoop -r -t d -d hme0 port 53
> > 0.01784 H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
> > 0.00004 H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
> > 0.00040 A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 211.9.244.15
> > 0.00001 A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 211.9.244.15
>
> This does indeed look odd..
>
> > 0.00462 H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
> > 0.00004 H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
>
> And this is worse.. yet another query for www.mail-archive.com 0.004
> seconds after receiving the reply to the first..
>
> Have you by any chance disabled the ipcache?

Yes,but I don't know how to disable the ipcache.

>
> > > Ok, this I have not tried. Maybe there is some slight error in
> > > acl processing causing the double DNS lookup.
> >
> > Why do you think so?
>
> It is just a speculation on why you see double DNS lookups. You are using
> dst acls while in my tests when making the 2.5.STABLE5 release I did not
> use dst acls, just plain forwarding. The DNS lookup for a dst ACL is
> performed in a different part of the code than the forwarding lookup. Both
> are cached in the ipcache.
>
> > How can I see if there is some slight error in acl processing causing
> > the double DNS lookup?
>
> Temporarily disable the use of the dst acls in your http_access,
> cache_peer_access etc access lists, then monitor DNS usage.

I did but got same result.
And when I used dnsserver(not internal DNS), I got same result again.

--
Tomi