*BSD News Article 63675


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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Route Table
Date: 15 Mar 1996 22:20:14 GMT
Organization: Private BSD site, Dresden
Lines: 26
Message-ID: <4icqeu$187@uriah.heep.sax.de>
References: <DoA2y4.ELx.E.fourthgen@fourthgen.fourthgen.com>
Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch)
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tomg@fourthgen.fourthgen.com (Tom Greenwalt) writes:
> Occasionally when a user connecting via SLIP or PPP hangs up their route 
> is left in the routing table like this (insert favorite IP address for x's):
> 
> Internet:
> Destination      Gateway            Flags     Refs     Use     Netif Expire
> xxx.xxx.xxx.xxx   link#2             UHLW        1      12
> 
> Does anyone know why a broken route is left behind like this sometimes?

I suppose you're using proxyARP for your SLIP/PPP connections?  So
after the connection broke, the next packet arriving destined for the
IP address that just disappeared defaults to the Ethernet interface,
and will be resolved through regular ARP.  The line you've been
quoting is a sign for this half-established route.  (The link#2 would
change to the Ethernet address once ARP was complete.)

That's the price of the proxyARP hack.  Avoid it if you can (e.g. by
allocating a different subnet for the SLIP/PPP connections).

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)