From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Rob Sterenborg" <rob@sterenborg.info>
Subject: RE: Iptables
Date: Fri, 20 May 2005 08:04:18 +0200
Message-ID: <20050520060303.34BE88EDCEB@smtp.sterenborg.info>
References: <200505200738.57268.chadley@pinteq.co.za>
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> Would it be safe to set the OUTPUT default policy to ACCEPT?
> Every time I set it to DROP I get locked out, I suppose it
> has to do with the fact that I have no rules for the OUTPUT chain.

A lot of people set OUTPUT policy to ACCEPT.
You can always do something like :

$ipt -P OUTPUT DROP
$ipt -A OUTPUT -p tcp --sport 1024: -j ACCEPT
$ipt -A OUTPUT -p udp --sport 1024: -j ACCEPT
$ipt -A OUTPUT -p icmp -j ACCEPT

This way a program cannot pretend to something like a web- or
mailserver. If you check "/proc/sys/net/ipv4/ip_local_port_range" you
see the local portrange (sport) your box will use. You can use this
range in your rules. E.g. you could  use "32768:61000" (if that is your
range) instead of "1024:".


Gr,
Rob