From: cldavis@speakeasy.net
To: netfilter@lists.netfilter.org
Subject: Re: Firewall Script Help
Date: Mon, 08 Mar 2004 21:14:41 +0000 [thread overview]
Message-ID: <W7941417650321211078780481@webmail3> (raw)
Anthony:
> -----Original Message-----
> From: Antony Stone [mailto:Antony@Soft-Solutions.co.uk]
> Sent: Monday, March 8, 2004 08:32 PM
> To: netfilter@lists.netfilter.org
> Subject: Re: Firewall Script Help
>
> On Monday 08 March 2004 8:12 pm, David Cannings wrote:
>
> > > 0 0 DROP tcp -- any any anywhere
> > > anywhere tcp flags:FIN,ACK/FIN
> >
> > As I understand it, this means "check the flags FIN and ACK, only match if
> > FIN is set and ACK isn't". This would match packets that only have the
> > FIN flag set, which I am fairly sure are valid. I may need correcting on
> > this issue, however.
>
> You are correct.
>
[...]
Packets that only have the FIN flag set are valid -- but I believe would be taken care of by the ESTABLISHED,RELATED rule. The FIN FLAG rule I entered just in case someone decided to bombard my systems with FIN flag packets only...
Is that an unneeded rule to protect against a DoS attack?
next reply other threads:[~2004-03-08 21:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-08 21:14 cldavis [this message]
2004-03-08 22:06 ` Firewall Script Help Antony Stone
-- strict thread matches above, loose matches on Subject: below --
2004-03-08 18:47 Christopher Davis
2004-03-08 18:49 ` David Cannings
2004-03-08 19:19 ` Christopher Davis
2004-03-08 20:12 ` David Cannings
2004-03-08 20:32 ` Antony Stone
2004-03-09 4:34 ` Mark E. Donaldson
2004-03-08 18:51 ` Aldo S. Lagana
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