Ok please bear with me here.
At the moment I have a single flat network as in the digram. What I would like to do is split it in to three seperate subnets. however my problem is that the Default gate way for the network currently is the router sitting off to the left of the digram.
Splitting up the networks is stright forward enough, and I now have three seperate networks as shown by the circles.
Red - 192.168.1.0 255.255.255.0
Green - 192.168.2.0 255.255.255.0
Blue - 192.168.3.0 255.255.255.0
However the router must stay on the same network (for the time being as the red network) so must have an address of 192.168.1.3 for instance
All devices on the network currently use the switch in buildign 63, 142 or 153 as there default gateway. and can all happly talk to each other.
what I want to know is what settigns do i need to set on these switchs, so that they route any non site data to the WAN router on 192.168.1.3
Is this possible and if so how, I am just looking for a generic way to do this, If a core switch can't find a route to an IP address to forward it to the router.
We only need to do this as an intermediate step during the upgrade as we can't change the routers IP address, and some devices on the 192.168.1.0 range need to keep there static IP address.
The idea is to segment the network, then sort out the servers and the last step will be sorting out the WAn routers.
I hope I have made it all clear but please ask if you need any more info.
Thank you Aaron