Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!decwrl!ucbvax!ucsd!rutgers!topaz.rutgers.edu!ron
From: ron@topaz.rutgers.edu (Ron Natalie)
Newsgroups: comp.dcom.lans
Subject: Re: Latest news on our ether errors
Message-ID: <18334@topaz.rutgers.edu>
Date: 25 Feb 88 16:23:10 GMT
References: <8403@g.ms.uky.edu> <4097@lll-winken.llnl.gov> <4126@lll-winken.llnl.gov>
Organization: The Office of Mismanagement and Bean Counting
Lines: 28
Keywords: ARP broadcasts, 4.2BSD networking, x.x.255.255 broadcast packets

THESE AND OTHER PROBLEMS CAN BE SOLVED EASILY!

TURN OFF IP FORWARDING ON THINGS THAT ARE NOT GATETWAYS.

If machines didn't try to forward apparently misaddressed
packets (or trully broken ones misdirected to them), these
cycles wouldn't occur.  A machine that has one interface that
is not performing some gateway function should just consider these
packets an error and discard them.

Below is a sample ADB which will show you how to turn off ip
forwarding on machines that you don't have source for (provided
they are 4.2 like).  If you have source, set the ipforwarding
variable to zero.


$ su				<--  You need to be root
Password:			<---   Can't help you here :-)
# adb -w -k /vmunix /dev/mem	<--  ADB the kernel
sbr f0711fc slr      649	<--  Crud output by ADB
physmem 1fe

_ipforwarding/X			<--  Find the current state
_ipforwarding:   1		<--  was turned on
_ipforwarding/W 0		<--  Not any more!
_ipforwarding:  0x0             =       0x0
_ipforwarding?W 1		<--  Fix it for the next reboot.
_ipforwarding:  0x0             =       0x0