Here is the scenario
We have 2 LAN's connected via DSL modems over an ISDN line.
Just got 2 2620's with one ethernet and one serial interface. I want to roll over slowly to the new scheme as I have some apps to test and a new NT domain to create and I'd like to keep it all separate and add in hosts one at a time - meaning that I want it all be fully functional from both subnets until the old is phased out. There are no switches that would get in the way of my config. Hubs only.
I want to change the address scheme of my corporate LAN for several reasons - my main issue is that I am locked out of my ISDN modem and cannot give it a new address. The network is small (both LANs) and I think static routes are the way to go.
Here is my approach, though I am having some trouble with the implementation:
Create the new IP scheme to work with the T1, set the current Corp address scheme as a secondary bound to the same ethernet interface. When all is said and done (assuming I still haven't been able to change the ISDN modem ip), I want that secondary to only serve the internet connection.
But... I can't ping anything on the original subnet from within the router unless I reconfigure that local ethernet interface address as the primary ip.
Does a secondary address, which shows as directly connected with sh ip route, still require any static routes to get out? Or is the ping failing during the reply back?
I can ping both the ISDN modem and the secondary 2620 ethernet interface (10.8.24.1/24 and 10.8.24.3/24, respectively) from the hosts on the network, as they are in the same broadcast domain.
I'm sure that I'm hanging up on something very fundmental here - thanks in advance for the help.