I've had my router up and running for 2 years, always working.

4 days ago the Nat that I set up to forward port 26 to my email server stopped working.  The settings are correct.  Long ago the public IP would change on occasion.  But that hasn't happened.  Checked the public IP is still the same.  The NAT settings point to the correct local IP.  The server has the settings that allow all IP's to communicate in.

I did no set up changes on either the router or the server.  I rebooted the router with no success.

Any ideas would be much appreciated.

Dave