not able to connect

Possible Duplicate:
Can’t view camera, keep getting a login screen

i have connected my linksys router directly to the dvr but i m only able to see the cameras only on local network but i m not able to see them thru my home i already made a hostname on dyndns pls any one can guide me when i go to the host name its asking me for username and password but when i put the unam and pass its not letting me access to my cameras pls any one can help thank you