Time Warner Wideband. I work around it by having a router behind the modem which firewalls off the rest of the network -- I treat the modem's side as completely untrusted. Not perfect, but it works.
I don't know who he has, but Time Warner does this in NYC. You have zero control over the configuration of the modem/router.
Sounds like a great defense in a file sharing lawsuit.
"Sorry, but I really have no idea how many people used my Wifi!"