A friend of mine has Vodafone DSL but the wireless part of the supplied modem/router isn't working. I'd like to remote in to see if he's messed up any settings, but it's not as simple as typing in his IP address.

Is it possible for me to log in remotely and look at his modem/router settings? Do I need to use https, a specific port for remote administration, does he have to enable it somehow?