my friends server timeout problem..Follow

hello everone, yeah ive got a friend thats been trying to play for months now,hes all paid up and can even play on other connections but when hes home he can only play for a couple minutes then hes cutof and given the error server timeout message. weve tried everthing we can think of, btw hes on an xbox 360..im told this might have somthing to do with his router not being configued to send and recieve packages or he needs to open ports..any help or info would be great thanks alot..Blixx of Ragnarok