The July 2004 TechNet Cable Guy article is titled “Path Maximum Transmission Unit (PMTU) Black Hole Routers” and describes TCP connection problems caused by PMTU black hole routers (that silently discard packets that must be fragmented for which the Don't Fragment flag is set) and some workarounds.

This is a common support problem in enterprise and Internet networking.

For a complete list of Cable Guy articles, see the Cable Guy archives.