Date: Sun, 28 Apr 2002 21:04:00 -0400 (EDT)
From: mrofilter@localhost
Reply-To: mrofilter@localhost
Subject: Re: GRE tunneling & ipfilters
To: Ramin Alidousti <[EMAIL PROTECTED]>

Quoting Ramin Alidousti <[EMAIL PROTECTED]>:
> Yes. Once when it comes through the physical interface. There, netfilter
> would see it as an IP packet with protocol 47 (GRE). And once when the
> packets come out of the GRE tunnel. Here again, netfilter would see IP
> packets but the protocol part would be TCP/UDP/ICMP...
>
> Try these rules to see the association:
>
> $IPT -A FORWARD -i <physical-interface> -p 47 -j LOG
> $IPT -A FORWARD -i <gre-interface> -j LOG
>
> Ramin
>

Thanks very much Ramin, one more question though.  Would the first rule above
actually be in the INPUT chain?  I'll be in school tomorrow morning, so I will
be able to experiment to get a better understanding.

Thanks again,
Mark Orenstein
East Granby, CT School System


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