2 external IP address mapped to 1 internal

Question

Is it possible to map the same internal IP address to two different external IP's on CISCO Firewall?

In the process of getting a new circuit so I would like to have them both mapped until I am ready to fully cutover.

Answer 1

With CISCO Firewall do you mean Cisco ASA I guess. If so, I never tried honestly but it should be possible with Static NAT. With ASA version prior to 8.3:

(config)# static($internal_net, $public_net), $public_IP1 $private_IP netmask 255.255.255.255
(config)# static($internal_net, $public_net), $public_IP2 $private_IP netmask 255.255.255.255

With ASA version 8.3 and later:

(config)# object network $MY_NAME1
(config-network-objct)# host $private_IP
(config-network-objct)# nat($private_net, $public_net) static $public_IP1

(config)# object network $MY_NAME2
(config-network-objct)# host $private_IP
(config-network-objct)# nat($private_net, $public_net) static $public_IP2

Then you need a proper ACL of course.