4.1 and netmask problem/solution

Roger Southwick rogers at dadla.wr.tek.com
Wed Nov 21 05:25:01 AEST 1990


Greetings.  I uncovered a problem with my new 4/490 (running 4.1 PSR A)
and ifconfig.

Our network(s) are class B based (134.YY).  We further sub-divide the
network into separate nets via a Network Systems Corp router.  We have 12
nets here, and our numbering starts at 11 (1-10 reserved for soemthing).

My 490 lives on 134.YY.NN, and has an IP address if 134.YY.NN.HH there are
also nets 134.YY.MM, 134.YY.PP, and so forth.  So I set the netmask to
255.255.255.0 (on a LOT of machines).

Now the problem.  On every OTHER machine I have (Sun3's (4.0.1), Sun SS1's
(4.0.3), Vaxen (4.3 BSD, Ultrix 3.1), etc), I can, after the machine is up
do a: 'ifconfig IF netmask 255.255.255.0' and it takes the command and
works fine.

On the 4/490 however, this won't work.  It takes the command, and even a
'ifconfig IF' shows things got set correctly, but then trying to 'ping -s'
anything  (including the machine itself via it's 134.YY.NN.HH address)
results in a "sendto: Host is unreachable" error.

Do a: 'ifconfig IF netmask 255.255.0.0', and the world is happy again.

I called this into Sun, and after spending some time on my own I found the
fix.  I found that by doing:

	ifconfig IF HOSTNAME netmask 255.255.255.0

things worked fine.

Just thought I'd pass this along.  I'd also be interested in hearing
anyone else's problems with this.

    -Roger      (rogers at dadla.wr.tek.com)
		UUCP:	...!uunet!tektronix!dadla.wr.tek.com!rogers
		ARPA:	<@RELAY.CS.NET:rogers at dadla.wr.tek.com>



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