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Date: Thu, 3 Feb 2005 05:30:13 +0200
From: Giorgos Keramidas <keramida@ceid.upatras.gr>
To: Graham Dresch <gdresch@spcint.com>
Message-ID: <20050203033013.GA3211@gothmog.gr>
References: <Pine.BSF.4.58.0502021403320.66014@dragon.spcplus.com>
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cc: freebsd-doc@freebsd.org
Subject: Re: Error in Handbook
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On 2005-02-02 14:11, Graham Dresch <gdresch@spcint.com> wrote:
>
> In Chapter 24 Firewalls:
> Section 24.6.5.7:
> Example ruleset #2:
>
> $cmd 020 $skip tcp from any to x.x.x.x 53 out via $pif setup keep-state
>                ^^^                                     ^^^^^
>
> DNS uses UDP, setup is inapplicable to UDP

Actually, DNS uses both UDP and TCP.  The size of a DNS UDP packet has
an upper limit.  If the data that needs to be transferred exceeds that
limit, TCP is used.

> The line should read:
>
> $cmd 020 $skip udp from any to x.x.x.x 53 out via $pif keep-state

It should probably remain as it is, and a TCP-specific line should be
added.  Ruleset #2 is supposed to be identical to ruleset #1, which
includes these rules:

    $cmd 00110 allow tcp from any to x.x.x.x 53 out via $pif setup keep-state
    $cmd 00111 allow udp from any to x.x.x.x 53 out via $pif keep-state

- Giorgos