Two different Routers and same subnet, is it possible?

[John Myhre]

Hi i have been presented with a problem that a friend of mine is having.

There is two different Cisco routers on different location.

example:

router1 : 10.8.10.1 (has DHCP/FTP server)

router2 : 10.8.12.1 (needs to talk to DHCP/FTP server on router1)

the router2 has different ip configured but is it possible to change this to the same subnet as router 1? like 10.8.10.4?

The DHCP/FTP server have been defined with scope 10.8.12.0 and on the Cisco switch on router2 its been configured (ip helper address DHCP-IP)

this works, the clients connected to router2 gets ip from DHCP server ,but there is no FTP traffic.

i figure its because the DHCP/FTP server doesent understand the other IP, so if its possible to setup a kind of mulitVPN to get the same subnet on router2 as router1 the FTP server can "see" the other router2 because it has the same subnet and ip range.

Thank you for any experience, i really stuck on this one

[blwright]

John,

to simply put it having two routers on the same subnet is not possible as the purpose of a router is to route traffic between DIFFERENT networks. In order to accomplish this you will need routers and switches that understand VLANs and VLAN tagging.

Hope this Helps

Blake Wright

Cisco SBSC Network Engineer