BT Voyager 2110 and IP forwarding

[peterv5]

Hi,

Our CCTV recorder box outputs on 192.168.1.4 and I want to send the pictures to an ip address, call it 2xx.2xx.3xx.1xx, using the above router This has been working in the past but has stopped working, because ( I think) the internal address changed from 192.168.1.3 to - 4. (Somebody else set it up) Now I can't get it to work. Every time I go to IP forwarding and type in the relevant addresses it fails because I put in the wrong netmask. I've tried leaving it blank and putting 255.255.255.0 and 0.0.0.0 with no joyfulness. Could somebody explain to me where I am going wrong?