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From: woodward@uicbert.eecs.uic.edu (Jeff Woodward)
Newsgroups: comp.unix.questions
Subject: subnetting on sunOS 4.1.1
Summary: why do i lose the first subnet after an increment in the third octet
Keywords: subnetting internetwork tcp/ip
Message-ID: <1991Feb6.163305.23887@uicbert.eecs.uic.edu>
Date: 6 Feb 91 16:33:05 GMT
Distribution: comp
Organization: University of Illinois at Chicago
Lines: 33

after having obtained a class-b internet number assignment, i am building a
subnetted network wherein i am using a subnet mask to create, obviously,
subnets.  my system consists of a number of sun sparcstations, partitioned
into small networks, each network being SLIP'ed back to another sun or to 
a XYLOGICS annex IIe terminal server running SLIP.  I am using U of Toronto
SLIP 4.0 w/the sun-supplied mclput panic fix.

since my subnet mask includes bits from the fourth octet, my networks
don't all begin with a zero in the fourth octet.
 
however, whenever i assign a subnet in which the fourth octet happens to
be zero, things don't work correctly.  i.e.  whenever i assign a network 
number in /etc/networks in which the last octet is zero, e.g. 

test.net.edu	nn.nn.nn.0  
 
where nn are any valid integers,  ... when i do this, and then do 
a    netstat -r    ,  the system shows the network number, not the
network name ( e.g. test.net.edu ) as it should.  also, the routing
funtions ( including broadcasts of RIP packets ) just don't work
right, and these zero-suffixed subnets don't get into other machines'
routing tables.

anybody know a good fix for this, or do we all simply have to throw 
away every sub-network number that ends with a zero octet. ( which amounts 
to 255 network numbers if you have subnet mask bits set from 
the fourth octet !!!! ) 

 
thanks in advance for your help.

jpw
univ of ill at chicago