It turned out that the camera had just happened to ship from the factory with the same IP address and netmask as the default gateway for that office network. This was odd because the IP address in question was within the range of public IP addresses owned by the company. In theory, a camera manufacturer shouldn't have been using that IP address, and who knows if it was chosen by request or was random chance, or if some other flawed logic was involved.
But the result was that every time this engineer powered on the camera, the level 2 switches in the area would start routing traffic to it, which (surprise, surprise) turned out not to know how to behave as a router.
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When the engineer, who was frustrated that he couldn't get his camera to work, turned it off again, the office network returned to normal.
The network admin who finally found the problem physically cut the cable uplinking the desktop switch to the rest of the network and left both halves of the cable on the engineer's desk -- along with a note sternly warning the engineer to never connect that camera to the office network again.
After this incident, IT disabled all unused Ethernet ports in the office areas. To get a port turned on for a second computer, networked printer, or other device required a written request to IT that was reviewed prior to having the port turned on. All IT-supplied unmanaged switches were promptly replaced with managed switches, most with their uplink ports turned off by default.
Moral of the story? Don't trust end-users (even engineers) with network equipment you don't control, and never trust the configuration of equipment from your suppliers. Also, cameras don't make good network routers.
This story, "The case of the random network problems," was originally published at InfoWorld.com. Read more crazy-but-true stories in the anonymous Off the Record blog at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.