WAN Routing with Multiple Subnets

[dmorgansmith]

Hello,

Please note firstly this isn't the way I want/would/would like to do this, simply just what we have inherited and are being told to do by the powers at be. We have two Cisco ASA's 5510/5505.

We have a leased line which terminates at a BT NTE Box with an IP of 217.68.255.42 and this has a link to the Cisco ASA 5510 with WAN IP: 217.68.255.41.

Now we have another firewall, and they want the leased line to be shared out to this as well, so we have put a switch in behind the NTE box, so NTE box to switch, switch to both firewalls. There were no IPs avaiable in the above range left (the 217.68.255.41-42) so we have been given two additional IPs in a totally seperate subnet. One of these IPs needs to go to the Cisco 5505, but what do we set as the default gateway for that route? The IP of the NTE box? A totally seperate IP? How would this routing work? New IPs are: 217.68.253.192/31      (217.68.253.192 - 217.68.253.193)

[guibarati]

You have to talk to the provider. The box has to have one IP that is reachable to the 5505. Either they need a secondary IP or they need to use an larger subnet for the two Asa's "this can be any network" then the box needs routes to reach each ASA IP. You would NAT the valid addresses on ASA and route it to the box on through this new transit network.

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