Date: Sun, 14 Jul 1996 00:22:05 -0700 (PDT) From: "JULIAN Elischer" <julian@ref.tfs.com> To: imb@asstdc.com.au (michael butler) Cc: archie@whistle.com, freebsd-hackers@freebsd.org Subject: Re: interfaces, routes, etc. Message-ID: <199607140722.AAA13889@ref.tfs.com> In-Reply-To: <199607140623.QAA00562@walkabout.asstdc.com.au> from "michael butler" at Jul 14, 96 04:23:47 pm
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> > > - 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 must admit that I was puzzled as to why it was necessary to add MAC > addresses into the route table. I thought they belonged in the ARP table and > nowhere else .. the routing table now IS the arp table, there IS no separate arp table any more.. > > > One very weird but non-reproducible case involved an ethernet interface > > that had been renumbered several times on the same class c network. > > The proper behaviour in changing an IP address, I'm told, is to send out a > packet advising everyone else on the local ether that their ARP table > entries for that particular IP address are now invalid. You can see this by > watching the output of a Cisco when you change its address. It seems that > FreeBSD doesn't do this when (typically) an "ifconfig delete" is done and > other hosts (or routers :-() on the same wire tend to get a little confused, it was the SOURCE address.. i.e. the packet claimed to be coming from the machine's OLD address. > > michael >
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