Network 1 cant’ see Network 2 – Both have DHCP

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Ok so this is the current setup:

Network 1:

  • Has its own DHCP
  • Is connected to a ADSL low speed connection and runs the Phone lines
  • Has the network (gateway)

Network 2:

  • Has its own DHCP
  • Is connected to a high speed ADSL2 connection and runs for the office computers.
  • Has the network (gateway)

Currently Network 1 cannot see Network 2 and vice versa.

I tried the following but I feel like I’m missing something:

  • I plugged Router1 into router2 (from eth1 port to eth1 port of the other router) and set a static route from router2 to router 1 for (

What are the issues with doing this? Am I missing something crucial? Do I also need to set it on the other router as well perhaps? This is not working currently.

Additionally, when I type in to access the router of the network 1 from network 2 , I still only get the router of network 2 now… so both and go to the same router.


Joining two networks requires (by definition!) a gateway, i.e. a host with two network interfaces, one belonging to network1, the other one to network2, allowing packets to pass from one to the other. In other words, this requires either a commercial router (to be configured to act as gateway only, not a router), or a specially crafted pc (it would be trivial to do with Linux). As a matter of fact, for a SOHO even an inexpensive Raspberry Pi would do.

There is however a much cheaper solution: unify the two nets into a single one, and you will have no need to buy or refit anything. This requires one word of caution: you need to disable the DHCP server on one of your two routers, or (if you decide to leave both DHCP servers running) you need to make sure that the two pools from which IP addresses are taken do not overlap.

A concrete example. You assign IP address to router1 (LAN side, of course) and to router2 (again LAN side). Then you can have the following ranges:



leaving as network mask (or /24).

At this point you can draw an ethernet cable between the two routers (draw an ethernet cable from each of them to the same switch, it’s the same), restart all of your machines (or allow some time for the new info to propagate to all of your hosts), and you are done.

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