Hypothetical Subnetting Question

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If I configured two hosts with the same IP address but different subnet masks, would it be possible for them to work parallel to each other over the same no frills switch (without connecting them to different routers for nat)

Now that I think about it, it would be two subnets with overlapping ip address ranges working over the same switch.

Is this possible or do you need to create two nats via routers?

I'm not actually trying to do this as I'm sure if it did work, it would probably not be optimal, just wonder if its possible.

Having different subnet values (yet still being a part of the same network) does not eliminate an IP address conflict. You could have two (or more) VLANs (which are separate networks) where your scenario would be possible on a more advanced switch. Note that NAT may not be involved with public-side addresses; if it is the same IP address on separate equipment then it should be separate networks.

@Yousef-Hegazi ,

The problem you run into is the possibility of discontiguous network addresses on routers. Routers can handle this if you're using routing protocols that support VLSM. For example, If I have Network A that is 172.16.10.0/24 on f0/0 and Network B 172.16.11.0/24 on Fa0/1.
By default, the Router will be able to do it but not of you have 172.16.10.0/24 on both interfaces. The router will send part of your packets to f0/0 and other parts to f0/1. So you will have packet loss.
Even NAT will not help here. NAT works off of setting your inside and outside interfaces. If you've got 172.16.10.0/24 on both inside interfaces and a single outside interface, it will NAT to both.

Cordially,
Ronnie Wong
Host, ITProTV