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Path: utzoo!mnetor!seismo!rutgers!topaz.rutgers.edu!hedrick
From: hedrick@topaz.rutgers.edu (Charles Hedrick)
Newsgroups: comp.unix.wizards
Subject: Re: rwho problems between 4.2 and 4.3 hosts
Message-ID: <12249@topaz.rutgers.edu>
Date: Mon, 25-May-87 19:35:35 EDT
Article-I.D.: topaz.12249
Posted: Mon May 25 19:35:35 1987
Date-Received: Tue, 26-May-87 03:51:13 EDT
References: <7523@brl-adm.ARPA>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 14
To: esj%bikini.cis.ufl.edu@RELAY.CS.NET


I assume the things that 4.2 doesn't see are broadcasts.  4.3 will by
default send broadcasts to 128.x.255.255.  4.2 only understands
128.x.0.0.  However you can set the broadcast address in 4.3 using
ifconfig.  I'd try a few until you get through.  Reasonable things
to try are 128.x.0.0 and 0.0.0.0, both of which are legal under the
old standards, and 128.x.255.255 and 255.255.255.255, both of which
are legal under the new standards.  Also, you should set
ip_forward to 0 on all machines that are not gateways.  You are
getting icmp errors back from 4.2 because they try to forward the
packets and can't.  This is a mistake.  Finally, I believe certain
implementations of 4.2 don't compute UDP checksums correctly.  If
you have any of these, you may have to turn off UDP checksumming
on all of your systems.  There's a kernel variable for that too,
with some obvious name like udp_checksums.