Hi, I'm one of apparently many which has problems with NAT being set to strict instead of open or moderate when playing COD Black ops. I tried port forwarding, unchecked firewalls, set it in DMZ etc etc. Now, nothing of these actions helped at all.
What did help is this;
get NAT moderate simply by adding it as a dhcp server and make a static ip. and if you do get strict once more, reboot the ps3 and you should have a moderate setting.
Hope this helps you lot as it helped me.