[4374] in linux-net channel archive
Re: Subnets - Can you have more than one?
daemon@ATHENA.MIT.EDU (Henry W Miller)
Sat Sep 14 10:13:45 1996
Date: Sat, 14 Sep 1996 08:31:52 -0500 (CDT)
From: Henry W Miller <mill0440@gold.tc.umn.edu>
To: Daniel Maldonado <danny@ct-ngnet.army.mil>
cc: "'Linux-net@vger.rutgers.edu'" <Linux-net@vger.rutgers.edu>
In-Reply-To: <01BBA1C3.25EB68A0@DMC_HOME.ngctdpi>
On Fri, 13 Sep 1996, Daniel Maldonado wrote:
> Hi everyone,
> I met a guy at work the other day and started talking about
> subnetting. He said that two computers on the same network can have
> different subnet masks. For example one computer can have a subnet mask of
> 255.255.255.0 while another could have a 255.255.248.0 subnet. I was under
> the impression that there could only be one network number in ever network.
> He said that the computers with different subnets would not be able to see
> each other but they would both be able to share the network and find other
> computers with their same subnet. Is this true? Maybe when it was
> explained in the Cisco router class that I took I misunderstood the
> instructor. Can anyone verify this? I need this info for our Linux
> systems.
>
Yes you can do this. the above subnet mask will cause soem problems
(that someone else already pointed out)
sor instalnce you could use 255.255.255.223 and use this subnet from
0-31, and then 255.255.255.239 on a netwrok from 32-47 (Or numbers real
close to this, I'm not sure exactly where the subnet bounderies lie
offhand) this mihgt be minorly useful if you don't want to run a cable,
and need some sort of firewall between the two networks. (you can run
the same netmasks as well) Understand that any secerity you gain from
this is easilly got around by anyone who konws what they are doing. you
probably want each subnet to use a different port on the router, to avoid
problems, though ip aliesing may be enough.
I recomend anyone considering this think carefully though, it is not a
secerity scheme unless you have nobody other then the true admins who
know anything about netwroking, a very unlikely thing. Do the extra
cabeling, to seperate your netwroks and save yourself a lot of hassle.
