From owner-freebsd-net Mon Aug 23 14:53:26 1999 Delivered-To: freebsd-net@freebsd.org Received: from khavrinen.lcs.mit.edu (khavrinen.lcs.mit.edu [18.24.4.193]) by hub.freebsd.org (Postfix) with ESMTP id DAA391575B for ; Mon, 23 Aug 1999 14:53:19 -0700 (PDT) (envelope-from wollman@khavrinen.lcs.mit.edu) Received: (from wollman@localhost) by khavrinen.lcs.mit.edu (8.9.1/8.9.1) id RAA23164; Mon, 23 Aug 1999 17:52:12 -0400 (EDT) (envelope-from wollman) Date: Mon, 23 Aug 1999 17:52:12 -0400 (EDT) From: Garrett Wollman Message-Id: <199908232152.RAA23164@khavrinen.lcs.mit.edu> To: George Chung Cc: "'freebsd-net@freebsd.org'" Subject: 3 newbie Q's on routes for multicast addresses In-Reply-To: References: Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org < said: > route add -net 225.0.0.1 -netmask 255.0.0.0 -interface 10.100.100.100 > Although this works, I'm not so sure about the semantics of the > netmask. It shouldn't work, since netmasks should be contiguous and you've created one that isn't. However, the radix tree is a fairly flexible data structure, so it's possible that all you've done is slow your routing computation down a little bit. The correct command would be: route add -net 225.0.0.1 -netmask 255.255.255.255 -interface 10.100.100.100 (assuming you only care about this one multicast group) or: route add -net 224.0.0.0 -netmask 0xf0000000 -interface 10.100.100.100 (if you want all muticasts in general to go out the same way). > It seems that a netmask of 224.0.0.0 is also legit, but I wouldn't > know how to explain the difference between using one over the > other. What does a netmask for a class D address really mean? The same thing a netmask for any other address means! An address/mask pair (V, M) matches any address Vx such that (V & M) == (Vx & M). > 3. Can someone point out the man pages for automatically adding this route > at boot up time? rc.conf(5). -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message