Re: ICMP (was: daily internet traffic report)

[Cedric Blancher <blancher () cartel-securite fr>]

Le lun 18/10/2004 à 17:12, james edwards a écrit :
> > I don't see the reason why it would cause a problem, as firewall is able
> > to spot ICMP related to server's IP connections as well...
> New connections to the server must be implecitally allowed, as there
> is no established state to refer to.

I guess that if you want to run a server behind a firewall, then you
have to allow some TCP or UDP connections to it... And you only have to
deal ICMP stuff for thoses connections, as others are prohibited, and
the firewall does this.

I really don't see where the problem is.

My point is just to show that we do have now solutions to filter ICMP in
a smart way that won't break PMTU discovery and stuff that rely on ICMP
messages reception...


PS : I think we could end this offline, we're far away from original
topic :)

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