Many providers will attempt to issue you the same IP address every time you connect. This may be what's happening.
When you do a ipconfig, you may just be releasing/renewing your local LAN IP. If the IP address of a ipconfig shows as 192.168.X.X, 172.16-31.X.X, or 10.X.X.X, then you are getting a private IP. To confirm your real WAN IP, visit a site such as http://www.speedtest.net/
, which gives your real IP in the bottom left corner of the flash app.
If you want to try to get a new one - turn your DSL modem off for 10-20 minutes, turn it back on and check it again. If you're getting the same IP, they may be issuing you an IP based on your MAC address.