I have 1 external IP address that is used for incomming mail. That address is pointed via static to my Barracuda web filter. My xchange server falls under the standard dynamic nat policy. One some domains I have been getting NDR bounce backs because the source IP address does not mach my MX record address (reverse dns).
188.8.131.52 is the external IP address for my internal host 172.16.1.1 (my barracuda)
184.108.40.206 is the external IP address for my internal dynamic nat. (so all other hosts appear under this address, which includes my exchage server).
Is it possible to mask / fake so that my exchange server appears to have the same external address as my barracuda to prevent these NDR reverse dns issues? However I do not want anything that goes to 220.127.116.11 to go directly to the exchange server.