[comp.sys.next] Experiences with networking on the NeXT

tyc@cbnewse.att.com (felix.a.lugo) (05/04/91)

	I've been having some trouble getting my NeXT to live in a non-NeXT
	network.  I've followed the manuals to the letter and my machine
	cannot communicate with anything other than another NeXT on the
	same subnet.

	At my location we have a campus network composed of several sub-
	networks each combining different platforms (Suns, AT&T, Amdahl, IBM).
	My NeXT is configured as a non-Netinfo (local) system.  Other systems
	ping my machine and they see it without problems, but if I try to
	ping them, I only get packets every once in a while (98% packet loss
	according to ping).

	The following is the output generated from "ifconfig en0":

en0: flags=23<UP,BROADCAST,NOTRAILERS>
        inet 135.1.156.2 netmask ffffff00 broadcast 135.1.255.255

	My subnet router is set to IP 135.1.156.254 (which is correct).

	All the network hardware has been verified to be functional by my
	site's support staff and I've successfully used other systems on the
	same network.

	Another NeXT on the same network (IP 135.1.156.3) suffers from the
	same problem (although both NeXTs can easily communicate with each
	other).  They just can't see anything that's not a NeXT.

	Has anyone encountered such a problem?  Have I setup everything
	properly?  HELP!  If NeXT is reading this, I could certainly use their
	support!

===============================================================================
Felix A. Lugo

E-Mail: (NeXTmail preferred)
   AT&T Bell Laboratories, Naperville, IL	Felix_A_Lugo@ATT.COM
						coco@ihcoco.att.com
   AT&T NeXT User Group				nug@ihcoco.att.com
   T.Y.C. Software, Lisle, IL			coco@ihtyc.att.com
===============================================================================

nerd@percival.rain.com (Michael Galassi) (05/05/91)

tyc@cbnewse.att.com (felix.a.lugo) writes:
>	The following is the output generated from "ifconfig en0":

>en0: flags=23<UP,BROADCAST,NOTRAILERS>
>        inet 135.1.156.2 netmask ffffff00 broadcast 135.1.255.255

>	My subnet router is set to IP 135.1.156.254 (which is correct).

The broadcast address must set all 1's in the positions that would be
masked out by the netmask anded with the ip address.
broadcast = (ip_address & netmask) | ~netmask
In your case,
broadcast = (135.1.158.2 & 255.255.255.0) | ~255.255.255.0
          =  135.1.158.0 | 0.0.0.255
          =  135.1.158.255

This needs to be changed in the /private/etc/hostconfig file.  Under
the 2.0 version of the OS these are the pertinent lines.

INETADDR=135.1.156.2
IPNETMASK=255.255.255.0
IPBROADCAST=135.1.156.255

Make the same change on your other next as well, I assume it is also
mis-configured.  NeXT does not do well with subnet masks using their
cute tools, you have to go and brute-force edit the standard files
rather often to make things work right in a subneted environment.

Hope this helps.  The only thing I don't understand is why this worked
between two nexts.  If I can help further mail me.

-michael
-- 
Michael Galassi				| nerd@percival.rain.com
MS-DOS:  The ultimate PC virus.		| ...!tektronix!percy!nerd