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From: Athan <netfilter@miggy.org>
To: "Collins, Kevin" <KCollins@nesbittengineering.com>
Cc: "'netfilter@lists.netfilter.org'" <netfilter@lists.netfilter.org>
Subject: Re: DNS/Router/Firewall question...
Date: Thu, 13 Mar 2003 16:52:41 +0000	[thread overview]
Message-ID: <20030313165241.GO1025@miggy.org> (raw)
In-Reply-To: <5DE7560BBF09D6119ED100B0D03D8426013923@MAIL-SERVER>

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On Thu, Mar 13, 2003 at 10:36:34AM -0500, Collins, Kevin wrote:
> When I have the machine running as a router (i.e. ip forwarding enabled, no
> firewall rules in place) everything works fine.  When I start my firewall,
> DNS slows down to a crawl.  It works, but it works so slow that it feels
> like it's not.

  First guess is that whatever app is trying to 'do dns' is first trying
a DNS server that is NOT responding due to the firewall rules, and after
timeouts ends up trying one that DOES work.

  So, if it's a unix-like machine inside the network seeing the problem,
what's in the /etc/resolv.conf ?

  When a lookup is attempted from an internal machine with the firewall
up what does a 'tcpdump -ni <extif> port 53' show ?  You may want to run
a similar tcpdump on the appropriate internal interface too to see the
difference.

-Ath
-- 
- Athanasius = Athanasius(at)miggy.org / http://www.miggy.org/
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	   "And it's me who is my enemy. Me who beats me up.
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  reply	other threads:[~2003-03-13 16:52 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-03-13 15:36 DNS/Router/Firewall question Collins, Kevin
2003-03-13 16:52 ` Athan [this message]
2003-03-13 20:15 ` Bill Davidsen

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