ICMP traffic

[Charles Lacroix]

On Monday 14 August 2006 09:42, Cristiano Deana wrote:
> 2006/8/14, Charles Lacroix <clacroix at cegep-ste-foy.qc.ca>:
> > i was wondering which icmp type packets people accepted on there
> > production servers.
>
> did you read firewall(7) ?

I just checked it and it's talking about ipfw, i searched the man page for 
icmp rules and found this little block.

Thanks for the hint.

     # It is important to allow certain ICMP types through, here is a list
     # of general ICMP types.  Note that it is important to let ICMP type 3
     # through.
     #
     #       0       Echo Reply
     #       3       Destination Unreachable (used by TCP MTU discovery, aka
     #                                       packet-too-big)
     #       4       Source Quench (typically not allowed)
     #       5       Redirect (typically not allowed - can be dangerous!)
     #       8       Echo
     #       11      Time Exceeded
     #       12      Parameter Problem
     #       13      Timestamp
     #       14      Timestamp Reply
     #
     # Sometimes people need to allow ICMP REDIRECT packets, which is
     # type 5, but if you allow it make sure that your Internet router
     # disallows it.



-- 
Charles Lacroix, Administrateur UNIX.
Service des télécommunications et des technologies
Cégep de Sainte-Foy
(418) 659-6600 # 4266