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From: jbn@wdl1.UUCP
Newsgroups: net.dcom
Subject: SUN IP net warnings
Message-ID: <683@wdl1.UUCP>
Date: Tue, 3-Sep-85 20:08:43 EDT
Article-I.D.: wdl1.683
Posted: Tue Sep  3 20:08:43 1985
Date-Received: Sat, 7-Sep-85 13:38:15 EDT
Sender: notes@wdl1.UUCP
Organization: Ford Aerospace, Western Development Laboratories
Lines: 19
Nf-ID: #N:wdl1:11700022:000:1028
Nf-From: wdl1!jbn    Sep  3 14:03:00 1985


      We have observed SUN 2.0 units using some strange Internet addresses not
their own.  During booting, they generate protocol 77 packets with various
source IP addresses on network 0, sent as broadcasts to destination addresses
of [0,0,0,0].  They will also send out ARP information for these strange
net 0 source addresses.  So, if there is a SUN on your Ethernet, it may
be a good idea to ignore all IP datagrams from net 0.  Sites with gateways
to the ARPANET should be especially careful here.
      SUNs also use the "rwho" protocol, which is useful in simple
environments but tends to be obnoxious on large ones with long-haul links.
Rwho tells all stations who is logged in on each station, by periodic
broadcast.  This is generally undesirable on geographically distributed
networks.  Just remove the invocation of the "rwho" daemon from the "rc" file 
to turn this off.
      Finally, Sun release 2.0 does NOT have the congestion fixes of 4.3BSD;
it clogs up gateways just like the older releases.

					John Nagle