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Community Member

how to configure routing between 2 subnets via a router

hi need some info/help on configuring static routes between a router.

i have a test lab on 128.1.8.1 (255.255.0.0) and a core network on 128.1.0.1 (255.255.0.0) how do i goa balut routing information between the 2 subnets?

thanks

Jag

2 REPLIES
Community Member

Re: how to configure routing between 2 subnets via a router

You can't route between them because they are on the same network. To determine the network for any host, perform a logical 'and' between the host address and the mask. In your example:

host 1 10000000 00000001 00001000 00000001 =128.1.8.1

mask 11111111 11111111 00000000 00000000 =255.255.0.0

net 10000000 00000001 00000000 00000000 =128.1.0.0

host2 10000000 00000001 00000000 00000001 =128.1.0.1

mask 11111111 11111111 00000000 00000000 =255.255.0.0

net 10000000 00000001 00000000 00000000 =128.1.0.0

The result of the two 'anding' processes is the same. Therefore the two host addresses are on the same network. You will need to use a different address range for one of the nets or use a different mask. Example:

host1 10000000 00000001 00001000 00000001 =128.1.8.1

mask 11111111 11111111 11111000 00000000 =255.255.248.0

net 10000000 00000001 00001000 00000000 =128.1.8.0

host2 10000000 00000001 00000000 00000001 =128.1.0.1

mask 11111111 11111111 11111000 00000000 =255.255.248.0

net 10000000 00000001 00000000 00000000 =128.1.0.0

They now reside on different networks and can be routed.

Community Member

Re: how to configure routing between 2 subnets via a router

instead of using /16 subnet mask using /24 (255.255.255.0).

you can create one as primary IP address and the other as secondary IP address..

As described in the previous post, the way you have right it is not possible as it is same network and you DON'T need routing. just the regular ARP process would take care of the "reachability" issue as long as they are both in the same broadcast doman.

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