From: "Len L." <len@euler.com>
To: netfilter@lists.netfilter.org
Subject: RE: Blocking access to UDP port 53 (DNS) - Solution
Date: Mon, 11 Aug 2003 12:48:22 -0500 [thread overview]
Message-ID: <12CC60849165134FB7DF8570B621F4D51C89CD@mailxserver.euler.com> (raw)
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OK,
I got it. Here is the rule set I tried and had success (b.t.w. The DNS server is fire walled but is a standalone machine - no forwarding)
The answer was to reference DNS requests for port 25 only.
iptables -A INPUT --protocol udp --source-port 25 -s 63.143.210.0/24 -j LOG --log-prefix "XXX LOCAL UDP DNS XXX "
iptables -A INPUT --protocol udp --source-port 25 -s 63.143.210.0/24 -j ACCEPT
iptables -A INPUT --protocol udp --source-port 25 -j LOG --log-prefix "XXX EXTERNAL UDP LOG XXX "
iptables -A INPUT --protocol udp --source-port 25 -j ACCEPT
iptables -A INPUT -p udp -j LOG --log-prefix "XXX UDP DROP XXX "
iptables -A INPUT -p udp -j DROP
Also will drop the 25 sport reference on the internal side along with the logging as a final solution
Len Laulainen
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next reply other threads:[~2003-08-11 17:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-11 17:48 Len L. [this message]
2003-08-11 18:25 ` Blocking access to UDP port 53 (DNS) - Solution Ramin Dousti
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