Hello,
This seems to be a common problem but AFAIK, without a common solution. The
network map is as follows:
T1 to ISP
|
| /30 net
|
+----------------+
| cisco router |
+----------------+
| FastEthernet0/0
| a.b.c.1/24
|
(possible switch/hub here in future)
|
| a.b.c.2/24
| eth0
+----------------+
| |
| eth1 |---a.b.c.3/24-public-net-----> lan
| linux box |
| eth2 |---192.168.1.0/24-private-net---> lan
| |
+----------------+
Of course the above does not work as eth0 and eth1 are on the same subnet. So
far, I can see two possible solutions:
1. reassign the cisco to linux net to a private point to point /30 net. I have
tried with limited success.
2. reassign the cisco to linux net to a.b.c.1/29 (cisco) and a.b.c.2/29 (linux
box). This would give me a block of 8 between cisco and linux and would enable
me to add a switch/hub between to feed another host for backup mail relay and
dns server.
Questions:
1. Does a different subnet mask define a different subnet? Will the "two nics
same net" conflict be resolved by applying a longer mask to one subnet?
2. What is required to route through the linux box in "solution" 2 above? Is
this a case of "more specific, preferred route" applied?
3. Any relevant RFC's would be helpful.
4. Of course, ANY suggestions welcome.
TIA,
David Koski
david@KosmosIsland.com
