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Date:      Sun, 25 Feb 2001 16:12:45 -0500 (EST)
From:      <scanner@jurai.net>
To:        sthaug@nethelp.no
Cc:        marcr@closed-networks.com, freebsd-security@FreeBSD.ORG
Subject:   Re: /etc/rc.firewall fixes
Message-ID:  <Pine.BSF.4.21.0102251551230.66763-100000@sasami.jurai.net>
In-Reply-To: <67798.983133792@verdi.nethelp.no>

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On Sun, 25 Feb 2001 sthaug@nethelp.no wrote:

> You punch a hole in the firewall for the port(s) in question and for a
> limited amount of time (say 30 seconds). Useful to allow for instance
> DNS queries from clients on the inside.

	Right filtering ports. Thats not quite the same as filtering on
the state of a connection.

> Yes, of course you are somewhat vulnerable while you have this hole in
> the firewall. However, it's probably better than having everything wide
> open, while also being more *useful* than having all UDP closed.

	Very true. And I have done this for DNS. And you are right when
weighing the pro's/con's of full time UDP 53 and doing limited lifetime
expires of clients doing udp dns communications. This might be a good
modification to the existing default firewall rules. Assuming it breaks
nothing. Although you would still need to add a rule for TCP with dns. But
that you can filter by state and allow only established connections from
the clients.

=============================================================================
-Chris Watson         (316) 326-3862 | FreeBSD Consultant, FreeBSD Geek 
Work:              scanner@jurai.net | Open Systems Inc., Wellington, Kansas
Home:  scanner@deceptively.shady.org | http://open-systems.net
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