I have done this with the DCS6620 & 5300.
Camera:
Set an HTTP port (e.g. 1025) - pick one that is not is use
Set the IP address (e.g. 192.168.1.105) - these are usually set for you at first, pick one that is not in use
save that
Router:
Go to port range forwarding (it is under apps & gaming tab for my Linksys router)
The start and end ports are the same and what you gave the camera (e.g. 1025)
The IP address is the one you gave the camera (e.g. 192.168.1.105)
save that
Go to the status tab and find the IP address (e.g. 11.22.33.44) your ISP is giving you (this can change, but generally stays the same for a while)
Use that to get into the port (e.g. 11.22.33.44:1025)
Hope that helps or gets you in the right direction.
