[quote user="nijinski"] 116.25.87.49 this is my ip address according to whatip.org[/quote]
Rolf wrote: "I think you first need to verify that 220.112.193.167 is your current IP"
I can see your IP changes frequently. Currently your MX points to conneally.net, and conneally.net has an A record for 220.112.193.167. This would work, as long as that was your current IP, which it isn't. So somehow your dyndns isn't updating your current A record for conneally.net
Regarding the port forwarding:
First test and verify that you can reach MercuryS from your own network, by using telnet as you did: . If you do not get a response here, something within your machine is blocking inbound traffic (f.ex. windows firewall or another port blocking software)
Secondly, test and verify that you can telnet from the outside through your ADSL modem port forward based on IP number, telnet:116.25.87.49:25
Lastly, check that the DNS matches your current IP. You can easily do this with nslookup from a command window. And when this works, telnet:conneally.net:25 and you should be through the hardest parts.