From what I have read, UPnP should avoid having to mess around opening ports. I didnt try it myself as I am not at all clued up when it comes to networking. I was also busy last night trying to improve my network connection (keeps spazzing out with DNS errors) with the help of a more clued up friend.
Changed my wireless channel (found there was a fair amount of noise) and moved my router a little closer. If I still have problems tonight, I am wiring the PS3 to the router.
To be honest, I dont think there is any need to change the settings on the router to open up ports. From what I hear, MW2 had just as many MP probs on release. For now Im just going to complete the campaign at a leisurely pace and then hopefully the MP engine will be patched up when I finish. I started the campaign last night and tbh I thought it was pretty good.. Fast paced and really quite difficult on hard. Extreme should be a challenge!
It is a shame about the PS3s party problems, but I did have an awesome Blops online night last night, with some great kill:death ratios, despite the rest of my random team being generally sh*te most of the time. I must have scored at least +100 k/d by the end of the night.
The annoying thing is I never had any problems whatsoever with MW or MW2 when they were first released. The matchmaking in MW2 seemed a bit slower compared to the first in the series but nothing detrimental to the gaming experience. But then this is the first of the Treyarch Call of Duty games Ive played so Im not sure if this kind of thing is commonplace with them.
Hopefully a patch or two will iron it out.