Mail use the wrong ip

[Christian_Dextraze]

In my Cisco Firepower, I have set a NAT rule inside->outside that use my internal and external ip of my internal mail system.

That work fine, I receive mail, and I can connect to it from outside our office, but when I send a mail, it seem to use the external ip that is configured on my Cisco, is there another rule to make sure it use the right ip

[marce1000]

 - What mail environment are you talking about (product) ? 

 M.

[Christian_Dextraze]

We are using MDaemon, but I am sure it does not come from there, because I changed the external ip of the Cisco and now it use this new ip to send email, and lot of place refuse it because it say that my server IP address is missing a reverse DNS entry.

And I can't use the same ip, because the Nat rule reserve it

[Christian_Dextraze]

Well still did not found what I need to fix that, I guess I looking for a rule that take everything that come from an specific internal ip go to a specific external ip, can we do that?

[Christian_Dextraze · Accepted solution]

Well I finally managed to find how to do it.  I needed to add a manual NAT rule that I put first on the list of rules that take the internal ip and point it to the external one.