From owner-freebsd-hackers Sat Jul 13 16:46:13 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id QAA02881 for hackers-outgoing; Sat, 13 Jul 1996 16:46:13 -0700 (PDT) Received: from whistle.com (s205m131.whistle.com [207.76.205.131]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id QAA02870 for ; Sat, 13 Jul 1996 16:46:10 -0700 (PDT) Received: (from smap@localhost) by whistle.com (8.7.5/8.6.12) id QAA21532; Sat, 13 Jul 1996 16:45:32 -0700 (PDT) Received: from bubba.whistle.com(207.76.205.7) by whistle.com via smap (V1.3) id sma021530; Sat Jul 13 16:45:06 1996 Received: (from archie@localhost) by bubba.whistle.com (8.6.12/8.6.12) id QAA00884; Sat, 13 Jul 1996 16:45:02 -0700 From: Archie Cobbs Message-Id: <199607132345.QAA00884@bubba.whistle.com> Subject: interfaces, routes, etc. To: freebsd-hackers@freebsd.org Date: Sat, 13 Jul 1996 16:45:02 -0700 (PDT) X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk I'm finding some weird behavior in -current with regards to interface numbering, aliases, automatically generated routes, ARP entries, etc. One specific example... - When you bring an EtherNet interface up and ping some addresses on that network, you get automatically generated LINK layer routes (ie, arp entries). However, when you bring the interface down these routes do not automatically go away. [ I thought there was discussion about this before and agreement that "automatically generated routes should be automatically removed, and static routes should always be left alone." If so, I'd be happy to produce a patch for review. ] One very weird but non-reproducible case involved an ethernet interface that had been renumbered several times on the same class c network. It got into a situation where "ifconfig" clearly showed the address as a single number (and netstat showed sane settings as well), but pinging *certain* addresses on the ethernet would cause transmitted packets to have the old source ip address. In general, old alias addresses sometimes seem to "haunt" an interface long after they have been deleted. Another question: - Exactly what is the netmask, as configured on a point-to-point interface, used for? If anything, which address does it apply to, the local or the remote one? In FreeBSD: - The local and remote addresses do not need be part of the same network - The local address can be 0.0.0.0, but not the remote address - It is possible to set aliases address pairs on a point-to-point link which share the same destination, but not the same source I assume this is to be as flexible as possible for people trying to do funny things like half routing, etc. However, I don't understand the third one above; you should be able to have address pairs with the same source and different destination addresses; this would apply nicely to NBMA (non-broadcast multiple access) networks such as frame relay. My suggestions... - Automatically generated link layer routes get removed when an interface is brought down. - Allow NMBA type addressing on point-to-point links like this: tun1: flags=8051 mtu 1500 inet 1.1.1.1 --> 2.2.2.2 netmask 0xff000000 inet 1.1.1.1 --> 3.3.3.3 netmask 0xff000000 inet 1.1.1.1 --> 4.4.4.4 netmask 0xff000000 - Declare that any interface which has the POINTOPOINT but not the BROADCAST flag set, and which allows multiple (alias) address pairs, is by definition a NBMA network. -Archie ___________________________________________________________________________ Archie L. Cobbs, archie@whistle.com * Whistle Communications Corporation