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From: Archie Cobbs <archie@whistle.com>
Message-Id: <199708300622.XAA02291@bubba.whistle.com>
Subject: Re: ipfw protocols
In-Reply-To: <19970829153329.51631@aahz.jf.intel.com> from Alan Batie at "Aug 29, 97 03:33:29 pm"
To: batie@aahz.jf.intel.com (Alan Batie)
Date: Fri, 29 Aug 1997 23:22:46 -0700 (PDT)
Cc: hackers@FreeBSD.ORG
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> I'm using freebsd as a multicast router here, and I need to be able to
> allow igmp requests from a network so viewers can join a group, but
> block transmission of multicast packets in general.  ipfw only knows
> about tcp and udp, and from looking at the code and include files, it
> looks like the protocol specification interface is very limited.  You
> need to be able to actually specify the protocol by number if the name
> isn't known (e.g. rsvp is 42, I believe, and I'm sure there are others).

What version of FreeBSD (ie, ipfw) are you using? The current versions
in 2.2.X and -current support naming all IP protocols.

>From the man page:

     proto:

         ip                All packets match. The alias all has the same ef-

                           fect.

         tcp               Only TCP packets match.

         udp               Only UDP packets match.

         icmp              Only ICMP packets match.

         <number|name>     Only packets for the specified protocol matches
                           (see /etc/protocols for a complete list).

-Archie

___________________________________________________________________________
Archie Cobbs   *   Whistle Communications, Inc.  *   http://www.whistle.com