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New Member

Combining subnets

Good Morning.

I've got a question on how to combine subnets. I have 3 small closed networks, all utilzing a ip range of

These networks have no "outside" connectivity to the world and are located in 3 seperate physical locations.

To allow me to manage the applications and such that run on these networks, I am going to bring dedicated connections into a single location so that I can access these networks remotely.

Currently, I have a Point to point T1 connecting me to one network and I utilize Cisco 1841's on either end of that. However, I will pull fiber for connectivity to the other two nets. Both buildings are withing 500 feet of me.

What I want is to have all 3 networks have a Cicso router at the "network" end and a single router in my lan room that connects to all 3. Then, I want to be able to have one or more PC's to be able to connect to any of the 3 networks as needed.

Any thoughts as to the best method to implement this? I think the router side is pretty straight forward, but the PC connectivity is stumping me for the moment.



Cisco Employee

Re: Combining subnets

you should go the routing/swtiching or WAN forum for such question.


Cisco Employee

Re: Combining subnets

Hi Bob,

Would it be fair to say that you have one subnet and you need to divide it into three such that they all in the range but connected via routers?

say :

subnet 1------ router-------subnet 2

subnet 3--------|

If my understanding is correct then you can use the following subnets :

Subnet 1 : (

Subnet 2 : (

Subnet 3 : (


Please rate if it helps,



New Member

Re: Combining subnets

No. I have 3 distinct, geographiclly seprated closed networks, Each network was built with 192.168.1.XXX subnet. When originally designed, the 3 networks were to never connect to anything.

However, I now need to manage these networks remotely. Thus, I will be bringing a connection from each network into my workspace. Several of my staff need to be able to connect to any machine on these networks. The 3 still have to be "seperate", to ensure that no activity on one network crosses into the other.

So, from my terminal at my desk, when I bring up my remote desktop software, I need to be able to go to any machine on either net.

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