Well, it turned out to be a virus. Here's the eMail I received today.
"Hello, thank you for bringing this to our attention, this problem has been resolved. While not having direct access to the machine in question, it does appear that it was "not" engaged in active targeting of any particular machine within your address space, merely that it had been infected by a "worm" and was automatically attempting to spread its infection.
Until we can obtain direct access we have disabled that machine's connectivity. We apologize for the inconvenience this has caused you. Again, thanks for the notification."