Back in January, someone posted an anonymous and, at the time, unsubstantiated rumor about Paula Broadwell on her wikipedia page:
Petraeus is reportedly one of her many conquests.
The IP address of the anonymous poster has been blocked, but investigations determined that it was distributed by the tech giant Cisco. Cisco Systems has the military contract to do all overseas communication between bases in Iraq and Afghanistan and the United States.
While it's just speculation at this point, it makes all sorts of sense that someone in the military would 1) know about the affair, 2) be in Iraq or Afghanistan and 3) have a blocked IP address.
The way this thing has been going, whoever posted this will probably end up being a decorated general with rumored liasons to a top White House staffer. Yes, I'm just making that up, but things are already weirder than anyone would have reasonably imagined.