[Mistoffeles]

ok I'm missing something here...or someone is.

Are we talking about the local BIND9 service or internet DNS? Why would I care if the internal IP address can resolve to the mail server? I want people out on the internet to be able to send email on this server, not people on the local network (as there aren't any user workstations on the local network, this is a colocation site and has nothing but servers on the LAN).

All email users of this system will connect via the external IP address, not the address set in /etc/sysconfig/network-scripts/ifcfg-eth0. The only time there is a user on the LAN is when I am on-site with my laptop plugged into the router to work on the machine, which I really would rather never have to occur though sometimes I have no other choice.

I suppose I should also ask whether I should put the internal or the external IP address in /etc/hosts, since the only email users will be accessing it using the external IP address as returned from the internet DNS.

To put it more clearly, the server's IP address is 192.168.5.115 (LAN), this is 1:1 NATted on the router to 201.201.72.15 (internet) (examples, not the real numbers). To all users, the server's IP address is 201.201.72.15, there is not a single email user who will use 192.168.5.115.

This DNS stuff really makes me dizzy sometimes.