Re: GRE and PF problem

From: Stephen J. Bevan (stephen_at_dino.dnsalias.com)
Date: 07/15/05

  • Next message: Sten Daniel Sørsdal: "Re: GRE and PF problem" 
    Date: Thu, 14 Jul 2005 23:01:30 -0700
To: "Giovanni P. Tirloni" <gpt@tirloni.org>

    Giovanni P. Tirloni writes:
    > I don't know how PF keeps tracks of ICMP packets but there must be a
    > way for it to distinguish between a packet destined to 192.168.0.1 or 0.2.

    An ICMP ECHO REQUEST message has a 16-bit id field which can be
    altered by NAT to identify the originating machine.

    There isn't really an equivalent when using a minimal GRE header. If
    GRE checksums are turned on then the 16-bit Reserved1 field could be
    abused for NAT purposes.
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  • Next message: Sten Daniel Sørsdal: "Re: GRE and PF problem"