Is your DSL IP fixed or dynamic? Are your clients connecting via FTP, VPL or
to a website on your server? Are you running an e-mail server?
All connection types have different set-ups but if you're running a PPPoE
type account with a dynamic WAN IP, go to NO-IP.com and set-up forwarding to
your server otherwise your clients will never be able to find you.
I prefer a dynamic WAN IP personally, I can change it in seconds whenever I
want and NO-IP.com keeps my FTP, VPL and E-MAIL servers and Website locked
to my domain. Fixed IPs are HIGHLY overrated.