Cisco ASA 8.4.1 Destination Address NAT?

[boomish5052]

i have a situation where i have a deployed asa5505 running 8.4.1.

The client has an existing mail server that is located on their lan and has Port Nat's configured for the normal mail ports,  25,110,993,587 etc.

This works fine for mail inbound and for any user popping mail off the server externally or visiting the webmail interface from outside the network.

However when users inside the LAN try to connect through the ASA back inbound to the IP on the External Interface of the ASA they are unable to do so.

One solution i came up with is Split DNS.   and well this works it rely's on the users not changing their dns servers.

I was wondering if it's possible to do some sort of NAT that rewrites traffic destined for the above ports on the external IP to the Internal LAN Ip instead.

It's probably a dumb question but i wasn't able to find an answer perhaps i'm using the wrong terms to look for one.

In any event i was hoping someone here could point me in the right direction.

Thanks                  

[Jennifer Halim · Accepted solution]

You can only configure DNS rewrite if you have static 1 to 1 NAT, with static PAT as advised, DNS rewrite is not supported because with static PAT, there is potentially different internal IP mapping, hence the DNS rewrite can't accurately rewrite to the correct address.