[Techtalk] Networking question: Linking two public subnets via a pair of virtual interfaces.

[Mary]

Just an update, since I've only spawned a subthread not an answer. :(

On Wed, Apr 16, 2003, Mary wrote:
> The router has two virtual interfaces: eth0 and eth0:0. eth0 is
> 10.0.0.190 (on the external) and its gateway is 10.0.0.189. eth0:0 is
> 10.0.0.225 (on the internal).

OK, my short term solution is SNAT (source network address translation -
its just like masquerading except it is designed for an 'always up'
address with a static IP, which you normally don't get on dialup).  This
works, but is vaguely undesirable because 10.0.0.226 shouldn't have to
be disguised as 10.0.0.190 before it can communicate with the other
subnet. 10.0.0.226 is a routable address!

It seems that once I can get a router with two physical interfaces (ie
have its 10.0.0.190 on eth0 and 10.0.0.225 on eth1) the kernel will
consent to do proper routing without network address translation.

-Mary