Can I use Cisco 2650 as internal router only

[mdwu]

We just got acquire by another company and will move into their office. However, since we use windows 2000 AD domain, exchange 2000, dhcp, dns, etc and they don't, I want to be able to separate the two networks, so i can keep the same internal ip address with my dhcp server and still able to have internet access, run email servers using their main internet connection

Also, since they use different IP address range in their network from their dhcp server. We cannot use their ip range.

Since my cisco 2650 has fa0/0 and fa0/1. Can I use the 2650 just as a internal router to separate my network and their network. And then have the router route between fa0/0 and fa0/1. Let say fa0/0 is to their network and fa0/1 is internal to ours. The router also have 2 serial port for T1 which we are using right now. But once we move to their office, the router will be only a internal router and the two serial port will not be plug in. Please help, and if possible provide sample config.

This is what i think

My Internal Network fa0/1
|
My Cisco 2650
|
Their Network fa0/0
|
|
Their Cisco Router
|
Internet

 

[lgarner]

Sure. The configuration couldn't be simpler. The short version is:

int fas 0/1
ip address <your ip address> <your mask>
int fas 0/0
ip address <their ip address> <their mask>

&quot;Their Cisco Router&quot; will also need a route back to your network via &quot;My Cisco 2650&quot;, unless you're using a dynamic routing protocol.

 

[mdwu]

Thanks Igraner, you are the best. No we do not use dynamic routing, so what needs to be add on their main router. sorry i am fairly new with cisco. thanks.