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From: kellen@UV4.EGLIN.AF.MIL ("Dan Kellen")
Newsgroups: comp.protocols.tcp-ip
Subject: I need help with subnetting
Message-ID: <9006081143.AA02799@ucbvax.Berkeley.EDU>
Date: 7 Jun 90 00:48:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 50


   I need some routing/subnetting help.

   We have a class B network.  We are not doing subnetting, but have been
   assigning addresses as if we were; each building has a unique third octet.
   The buildings are tied together with ethernet bridges, not IP routers.

   We have a department that has just aquired several SUN's and want's to
   use one as a gateway to the others.  I gave them IP addresses with a new
   third octet for all of there machines, and an address with the third
   octet of the building they are in, for the second interface on the 
   gateway machine.

   Now comes the problem.  The SUN gateway doesn't gateway!  I can get to 
   the gateway from the main network, but not to/from the other SUN's.

   Since I'm not doing subnetting, the SUN's two interfaces have different 
   IP addresses, the same netmask, but are on two different Ethernet's.  

   I then changed the netmask of the interface to the other SUN's to mask 
   the third octet.  Now the SUN's can talk.  But, the SUN's IP interface 
   to the rest of the network doesn't work.  

   What am doing wrong?


   How about a picture:


        network: 129.61.2.0                network: 129.61.9.0
        netmask: 255.255.0.0               netmask: 255.255.255.0


                                                       +-----+
                                                       |     |
                    /\                           +-----| SUN |
                    |                            |     |     |
                    |             +-----+        |     +-----+
                    |      129.61 |     | 129.61 |
                    |-------------| SUN |--------+
                    |        2.40 |     | 9.2    |
                    |             +-----+        |     +-----+
                    |                            |     |     |
                    |                            +-----| SUN |
                    \/                                 |     |
                                                       +-----+

   Any help appriciated.
   Dan
   kellen@uv4.eglin.af.mil