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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: net@freebsd.org
Date: Thu, 08 Nov 2007 20:08:52 +0100
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Subject: pf misfeature
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Given appropriate definitions for $eth and $lan, you'd expect the
following rule to simply pass all traffic originating from and destined
for the LAN:

  pass on $eth from $lan to $lan

However, in pf, "keep state" is *implicit* (why?), so you'd expect it to
turn into something like this:

  pass on $eth from $lan to $lan keep state

but what you actually get is this:

  pass on $eth from $lan to $lan flags S/SA keep state

which only matches TCP handshakes, so your UDP streams are screwed.

Workaround: explicitly specify TCP and UDP, causing pf to split the rule
into two:

  pass on $eth inet proto { tcp, udp } from $lan to $lan

becomes

  pass on $eth inet proto tcp from $lan to $lan flags S/SA keep state
  pass on $eth inet proto udp from $lan to $lan keep state

There does not seem to be any way to turn off this misguided rewriting
of firewall rules.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no