Unable to access website with dynamic DNS

wow I didnt know no-ip.com gave you a MX record (or I wasnt paying attention)... I think I will try and setup an email server tonight just for practice. I will make sure however that I don't set it up as an open mail relay ... I had to goto a business and fix that problem cause they were wondering why their IP address was being blacklisted by email companies.

What made me more angry was that the people who setup the email in the first place didnt put in the appropriate security in for the amount of money they were paid. :x

i have set up with no-ip....
its the only one workin...and do i need to specify the port at the back of the url? coz without it...i cant seem to access the page....its a timeout.i get an error.
but with the port number at the back, :81...i can access the page easily....

Obviously you'll have to specify the port if its not running on port 80 otherwise how will the browser know where to look for it ??