Combining 4 C-class networks: how?
I run Debian potato Linux (upgrading it weekly) within a network
that others have setup for Microsoft Windows 95/98.
This network has (over the same ethernet cables)
computers and printers covering 4 C-class networks
as follows [first 2 digits altered],
10.129.206.0
10.129.207.0
10.129.208.0
10.129.209.0
My computer has the IP address,
10.129.208.230
HOW DO I GET MY LINUX COMPUTER TO WORK WELL IN A NETWORK OF 4 C-CLASSES?
Here are the two approaches I have tried.
1. Sub-networking
I largely followed ideas in the IP Sub-Networking mini-HOWTO.
In
/etc/network/interfaces
I set,
address 10.129.208.230
netmask 255.255.252.0 #notice the different netmask
network 10.129.206.0
broadcast 10.129.208.255 #no broadcast address seems correct.
gateway 10.129.208.1
Unfortunately, looking at the configuration of Microsoft computers
on our network, each computer has the standard C-class
netmask 255.255.255.0, so probably a standard broadcast address.
As a result, the above settings do not seem to properly work
with all 4 C-class networks running over our common ethernet wire.
In particular, the Debian "arpwatch" software sees
all 10.129.{206,207,209} addresses as bogons, filling up /var/log
with warnings.
I last tried this approach 6 months ago.
2. Aliasing
I largely followed ideas in the IP-alias mini-HOWTO.
I turned on IP Aliasing in the kernel, then put the following in
/etc/network/interfaces
iface eth0 inet static
address 10.129.208.230
netmask 255.255.255.0
network 10.129.208.0
broadcast 10.129.208.255
gateway 10.129.208.1
iface eth0:0 inet static
address 10.129.206.1 #but this is another computer's address
netmask 255.255.255.0
network 10.129.206.0
broadcast 10.129.206.255
gateway 10.129.208.1
iface eth0:1 inet static
address 10.129.207.1 #but this is another computer's address
netmask 255.255.255.0
network 10.129.207.0
broadcast 10.129.207.255
gateway 10.129.208.1
iface eth0:2 inet static
address 10.129.209.1 #but this is another computer's address
netmask 255.255.255.0
network 10.129.209.0
broadcast 10.129.209.255
gateway 10.129.208.1
This approach worked well for Samba for 5 minutes until, I presume,
other computers like 10.129.206.1 conflicted with
my multiple assignment of IP addresses to the same ethernet card,
including this very "address 10.129.206.1" above.
Of course, I have but one IP address, so my eth0 card
should be assigned but one IP address.
I last tried this approach 2 days ago.
So, you can see I would like all 4 C-class subnets to be somehow
recognized as one network by my Debian computer,
which would probably require the following settings,
a. address of my eth0 interface
10.129.208.230
I can get but one address for my computer from my administrators.
I don't need all the IP aliasing that lets my computer respond
to several IP address; I only need my computer to interract
in a network that has 4 C-class networks.
b. broadcast addresses
10.129.206.255
10.129.207.255
10.129.208.255
10.129.209.255
I believe I need all these standard C-class broadcast addresses
because all other computers on the network use one
of these four lines as a broadcast address.
c. netmask and network
I don't know what I need for these.
Indeed, with the problems I have with trying to solve
my networking problem through IP subnetworking and IP aliasing,
I am unsure what approach to use with the above (a) and (b) restrictions.
Any ideas?
--
Jim Burt, NJ9L Fairfax, Virginia, USA
jameson@mnsinc.com http://www.mnsinc.com/jameson
jameson@pressroom.com http://yuet.com (coming soon)
nj9l@qsl.net (202) 690-0380 (work)
You can only find truth with logic if you have already found truth without it.
-- G.K. Chesterton
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