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Date:      Mon, 27 Jul 1998 09:06:45 +0100 (BST)
From:      Jay Tribick <netadmin@fastnet.co.uk>
To:        Jesse <j@lumiere.net>
Cc:        freebsd-security@FreeBSD.ORG
Subject:   Re: ipfw rules to allow DNS activity
Message-ID:  <Pine.BSF.3.96.980727090344.11044D-100000@bofh.fast.net.uk>
In-Reply-To: <Pine.BSF.3.96.980727001106.118A-100000@leaf.lumiere.net>

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| I'm thinking of changing one of my boxes which is running bind (performing
| primary secondary DNS functions) from
| allow-anything-except-things-specifically-denied ipfw rules to
| deny-everything-except-things-specifically-allowed rules (open vs closed?
| hehe). Anyway, I was wondering what are the minimum rules necessary to
| allow DNS queries/transfers from other servers to my server, and also to
| allow queries from my server to other servers.
| 
| I tried a variety of rules from the rc.firewall file, but it's still
| blocking some traffic, so there must be something I'm missing.

AFAIR you should just be able to explicitly allow data from port 53
(udp & tcp) to pass through.

i.e

ipfw add 0 deny ip from any to ip.ip.ip.ip:255.255.255.255 
ipfw add 1 allow tcp from any to ip.ip.ip.ip:255.255.255.255 53
ipfw add 1 allow udp from any to ip.ip.ip.ip:255.255.255.255 53

(Don't quote me on the above.. I don't tend to use ipfw and there's
probably a better way of defining the above rules, for example, you
may not want to deny packets but simly drop/reject them - depends
how much info. you want to give out to script kiddies ;)

Regards,

Jay Tribick
--
[| Network Administrator | FastNet International | http://fast.net.uk/ |]
[|        Finger netadmin@fastnet.co.uk for contact information        |]
[| T: +44 (0)1273 677633 F: +44 (0)1273 621631 e: netadmin@fast.net.uk |]



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