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From: lyle@hpindda.HP.COM (Lyle Weiman)
Newsgroups: comp.sys.hp
Subject: Re: router
Message-ID: <4310079@hpindda.HP.COM>
Date: 5 Dec 89 20:39:43 GMT
References: <469@ntcsd1.UUCP>
Organization: HP Information Networks, Cupertino, CA
Lines: 23

>> Are there any places, other than netlinkrc, that update the routing
>> tables.  
>> 

The routing table can also be affected by ICMP Redirects.  When a Redirect
arrives, directing this machine to send packets destined for a certain address 
via a certain gateway, a routing table entry with those values is created.
Thus, it can happen that, over time, additional entries are made to the table.

Redirects often are generated by gateways which receive packets from a host,
but find (thru their own tables, routing protocol-derived information, etc.)
that there is a "better route" to that host.  When this happens, they still
forward the original packet, but they send an ICMP Redirect to the sending
host, informing it that a better route exists.  HP systems, as of about
release 2.0, have made use of these Redirects."

These new entries are definitely from redirects, as they are each for a
single host, rather than for a network.

Your posting specifically mentioned a 3.1 system, but I thought I'd just
quickly mention that Release 7.0 adds the capability to run /etc/gated,
which "understands" routing protocols (RIP, HELLO, and IGRP).  gated
can and does affect the routing table entries.