Date: Wed, 21 Feb 2001 11:43:08 +0000 From: Adam Laurie <adam@algroup.co.uk> To: Nick Sayer <nsayer@quack.kfu.com> Cc: freebsd-security@freebsd.org Subject: Re: /etc/rc.firewall fixes Message-ID: <3A93A9CC.BC1D39FB@algroup.co.uk> References: <200102202005.f1KK5kv83619@medusa.kfu.com>
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Nick Sayer wrote:
>
> I would like to suggest a new "simple" firewall configuration.
>
> I recently put a security fix in the prototype /etc/rc.firewall
> stuff to close up a rather glaring security hole.
>
> The old stuff did
>
> pass udp from any 53 to ${oip}
>
> which allows someone to communicate, for instance, with port 2049 so
> long as they bind their end to 53. The state keeping stuff is the
> correct solution.
>
> My proposed "simple" firewall config goes something like this:
>
> check-state
> pass udp from ${mynet} to any keep-state
> pass all from ${mynet} to any
> pass tcp from any to any established
> pass icmp from any to any
>
> This simple set of rules represents a simple one-way set up. UDP is
> allowed to go out, and matching replies are allowed to come back in.
> TCP sessions are allowed to go out only.
>
> By itself it is not a complete ruleset, but I think it is a better one
> than any of the examples we presently have. I haven't committed this
> because I wanted to start some discussion first and commit the resulting
> consensus.
while you're at it, all the variable definitions need to be moved out of
rc.firewall itself and into rc.conf. i would also like to see a "mobile"
section for ppp/dialup and will contribute mine if required... good luck
with getting a commit! :)
cheers,
Adam
--
Adam Laurie Tel: +44 (20) 8742 0755
A.L. Digital Ltd. Fax: +44 (20) 8742 5995
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