forwarding ports with a openreach modem

[#1]

Hi i have got fttc with a bt open reach modem im having real trouble forwarding ports i know i have the settings correct on my (monwall) box aparently my openreach modem is doing nat spoofed ip address. I have no idea what this is or if it is correct can anyone shed some light on this for me pls.

[#2]

It won't be the Openreach modem you need to open ports on - this is just a pass through device
Which ports are you trying to open? Has your monowall box worked before ok?
Edit: Probably worth checking the firewall here is off - https://portal.plus.net/my.html?action=firewall

[#3]

Hi thanks for the reply. I'm aware the modem its self don't block ports but ive been told that they spoof the external ip address meaning the external ip i have is not the one on the net.
Yes it all did work before with the same setup that's the part that confuses me.

[#4]

Thanks AndyH it looks like it was the firewall you pointed me to after all I just needed to reboot my monwall box after turning of firewall and all is working sweet thanks I would never of guesed that.