Getting 4.2BSD to Understand Subnetted Network

[Neil Rickert]

In article <183 at bvsatl.UUCP> root at bvsatl.UUCP (Super user) writes:
>In article <1873 at fallst.UUCP>, tkevans at fallst.UUCP (Tim Evans) writes:
>> 4.2BSD seems not to understand subnetting, so the
>> first such machine on the net sees only itself and a few
>> others (386's with an older TCP/IP) which also don't understand
>> subnetting.
>> 
>Assuming that you are using a decent router to connect your subnets,
>it should be able to proxy arp for the hosts on a different subnet

 The original complaint is not completely clear.  If there is a problem
with any TCP communications, then proxy arp should handle it.  But the
complaint may have been the inability to see 'rwhod' messages, etc.  In this
case there is not much you can do about it.  The problem then is not the
subnet mask, but the broadcast address.  Since the 4.3 broadcast address
specifies all '1' bits for the host section, whereas 4.2 broadcasts use
all '0' bits.  So solving the subnet problem is not a complete answer.

 If broadcasts are real important, you can probably configure the 4.3
hosts to use the 4.2 broadcasts and subnetting.  But that will prevent them
seeing 4.3 broadcasts (such as routing packets), so the cure may be worse
than the disease.

-- 
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  Neil W. Rickert, Computer Science               <rickert at cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115                                   +1-815-753-6940