Exchange on a local subnet, no published IP.

[TravisM]

The site that I'm working at currently has an Exchange server that is sitting behind a NAT enabled router. The Exchange server has a local subnet IP only, 192.168.1.4, it has no real IP on the Internet.

I must be missing something here, but I have no idea how this server is getting mail. We're making some organizational changes that are going to cause us to move our Domain to new DNS servers. Can anyone explain exactly how, or why this server is able to recieve mail without a valid IP, so that I can get the new DNS provider to set coordinate with me?

Thanks for your help...

 

[ashleym]

The router or firewall is natting a real world IP to the internal IP of the mail server. Check the DNS for your domain, there has to be an MX entry that will resolve to a real world IP, that real world IP is pointing to your firewall/router which uses NAT and voila you have email!!!

Ashley

 

[lanman67]

Whoever holds the DNS for your domain must update/add an MX Record that says forward all mail sent to mail.<domainname>.com to public IP xxx.xxx.xxx.xxx. This will be the public IP of your router. Your router is then setup to forward inbound/outbound smtp traffic on ports 110 and 25 to your local exchange server.