Your cable company could be monitoring your activity, I personal suffered a
lock down by mine during a VPN session. I was transferring 2 gigs worth of
back-up data back to a client when I lost the connection, everything was
good with my side of the network so I logged into my cable modem to find
that they had issue some sort of command and locked-down my Linksys Modem,
everything and been locked, all of my provisional rating were 0Kbs, it was
ten minutes before I got any connectivity back to the internet. I was told
by a Help Desk Support Technician that they block TCP 135-139 TCP 445 TCP
6667-6669, this was with my provider and your provider may very what they do
and don't block on their end, and what they do and don't monitor.