An anonymous reader sends this quote from a blog post about a very odd technical issue and some clever debugging:
"Packets of death. I started calling them that because that’s exactly what they are. ... This customer location, for some reason or another, could predictably bring down the ethernet controller with voice traffic on their network. Let me elaborate on that for a second. When I say “bring down” an ethernet controller I mean BRING DOWN an ethernet controller. The system and ethernet interfaces would appear fine and then after a random amount of traffic the interface would report a hardware error (lost communication with PHY) and lose link. Literally the link lights on the switch and interface would go out. It was dead. Nothing but a power cycle would bring it back. ... While debugging with this very patient reseller I started stopping the packet captures as soon as the interface dropped. Eventually I caught on to a pattern: the last packet out of the interface was always a 100 Trying provisional response, and it was always a specific length. Not only that, I ended up tracing this (Asterisk) response to a specific phone manufacturer’s INVITE. ... With a modified HTTP server configured to generate the data at byte value (based on headers, host, etc) you could easily configure an HTTP 200 response to contain the packet of death — and kill client machines behind firewalls!"