Please configure well the network settings! there must be something you missed

Well . i have connection probles now and then .. and with me it because my wireless router is downstairs and my ps3 is upstairs. i was angry trying to sign in all the time and connection just getting lost .. so i took my ps3 dowm stair where my connection and signal strengh was very high on 95 % where as upstairs it was 40% 20 sometimes .. thats cause alot of issues with connection on games. so trying moving your ps3 lil closer.. mines back up in my room .. i just put the router up higher. it's on about 60% noww.. not to bad i suppose lol
your computers firewall may also block certain port connection. but thats all i know really. let me know if it helps

Not uncommon. Seems to happen after a match has ended due to poor connection. I turn off the PS3 and the router, Establish a new DSL connection then turn the PS3 back on. Also I have reverted to an ethernet (wired) connection from router to PS3 as I found the wireless connectivity on the PS3 very flakey, even with good signal strength. I only have a 2mB down and 500k up link as I live 3 miles from the exchange with only copper connectivity to my area. With CoD the difference between 3 and 4 bars is significant when playing, especially if like me you only use rfles and bolt actions (well running and gunning with MP40 gets so dull unless you are just interested in seeing your name at the top of the kill list)

I get 100% signal all the time but i still have problems connecting with friends.. my router is also wuite far away from the ps3..

i read somewhere that magnetic interferance can disrupt your signal.. try removing large metal objects such as your dvd players and thing away from the ps3 or vice versa and see if it makes a difference. then try a wired connetion.

Ha i got the same promblem but i fixed if

make sure your enternet cabie is in tight