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New Member

Can same subnet resides in different routers?

I only have two subnets form isp. I want to use some ips on our dadicated router outside the firewall. Is it ok to use same subnet on different router?

New Member

Re: Can same subnet resides in different routers?

If you subnet your subnet accordingly you can probably do it. You need a routing protocol with VLSM support (eigrp would be one choice for a small network). You might want to check out VLSM on CCO so you understand how to properly implement it for your given network. There is a hierarchy requirement that must be adhered to so it is impossible to say from your description whether you can do exactly what you are thinking of.

New Member

Re: Can same subnet resides in different routers?


If you are referencing connecting more than one router to the same physical segment and assigning an IP address on the same network, then the answer is yes; you can connect single interfaces from multiple routers to the same subnet. If you mean using the same network address space behind two different routers, then the answer is no; you must use different subnets for each network. Someone else responded to your question with a reference to vlsm and eigrp. vlsm will allow you take the address space from your ISP and break it down further into multiple, smaller networks.

Although, I seem to remember a white paper from Cisco from several years ago that said that they supported discontiguous address space across a routed boundary... A vpn tunnel would also allow you to extend address space to multiple segments, but this would over complicate things and is beyond what you're trying to accomplish.