Router

[vaishkhan161190]

Hi ,

I am configuring IP 10.0.0.1 255.0.0.0 on Router1 fa0/0 and when i am configuring IP 10.0.0.2 255.0.0.0 on Router1 fa0/2 then it's saying overlap.

But when I am configuring IP 192.168.1.2 255.255.255.0 on Router1 fa0/0 and 192.168.2.2 255.255.255.0 on Router1 fa0/1, it's working correct.

why overlaping problem is coming on only 10.0.0.0 255.0.0.0 network?

[Jon Marshall]

Because the 10.x.x.x IPs are from the same subnet ie. 10.0.0.0/8.

The 192.168.x.x IPs are from different subnets ie. 192.168.1.0/24 and 192.168.2.0/24.

The router will not let you configure the same IP subnet on multiple interfaces.

Jon

[vaishkhan161190]

Dear Mr.Jon Marshall,

i have 1 more question.

If i use /24 subnet, don't show overlap instead of /8. why?

[Ganesh Hariharan]

Hi ,


I am configuring IP 10.0.0.1 255.0.0.0 on Router1 fa0/0 and when i am configuring IP 10.0.0.2 255.0.0.0 on Router1 fa0/2 then it's saying overlap.

But when I am configuring IP 192.168.1.2 255.255.255.0 on Router1 fa0/0 and 192.168.2.2 255.255.255.0 on Router1 fa0/1, it's working correct.

why overlaping problem is coming on only 10.0.0.0 255.0.0.0 network?

Hi,

Rightly pointed by Jon. Just for more bit on information.

Normally routers do routing decision using there routing table and when you sign ip address to an interface it updates its routing table and you can see why you should be having two interface to route same ip subnet.

Also Routers are l3 devices and don not forward broadcast traffic but each interface of these devices represent a BC domain, so ip address configured on these interface will be unique with the Broad cast domain.

Hope it Helps..

-GI

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