No ONE will answer  to this quiestion ?????????? 
becouse I have same problem 
I have router connected to DVR 
DVR IP is 192.168.1.5 
in router port 80 is forwarded to 192.168.1.5 
when  in brouse from other network i go to Router internet Ip - Opening DVR web . but when I enter Sitecode and cms prt - it write NETWORK - FAIL 
what is the problem???