I have a client with an ASA 5510 and a pool of public IP numbers. His MX record points to an IP (155) that is not the static IP for the outside interface on the ASA (153). He has static nat configured for https and smtp on the IP (155) for Exchange. There is a dynamic nat for all outgoing traffic to use the interface IP. Some emails are being rejected since the reverse lookup does not match the MX record. Is it possible to configure nat so that outgoing traffic for the exchange server is a static IP (155) instead of the interface IP (153)?