joing 2 networks with same ip address

[carl_townshend]

If I have 2 networks, say 10/8 addresses on each end, would I have to nat the every address used, is there a quick way ?

[gpulos]

if you have 2 networks that have the ip address scheme - 10.0.0.0/8, then you can join them via Layer3 if the addresses on both sides do not step on each other.

or in the most likely case that the addresses do step on each other, then NAT to another ip scheme is acceptable, and yes each address would have to be NATed but you can use a NAT pool for automatic NATting.

or perhaps even easier, depending on your topology, is to join them at Layer2, ie: bridge the two networks together. with a router you can use IRB. (BVI interfaces)

see this link for IRB configuration:

http://www.cisco.com/en/US/products/hw/switches/ps5304/products_configuration_guide_chapter09186a00800f0a16.html

[carl_townshend]

how would the pool work though, would it just change the source address each time you look at the other network ?, as you wont know the real mapping ?

[jgretta]

If I understand you correctly, you want to do NAT with overalapping IP addresses. Here is a link that will give you an example.

http://www.cisco.com/en/US/partner/tech/tk648/tk361/technologies_configuration_example09186a0080093f30.shtml

[desai.jaideep]

Hi

Why dont you perform "transparent bridging" on both sides.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fibm_c/bcfpart1/bcftb.htm

Regards

JD