A product I'm working on consists of a primary component and two sattelite components. The sattelite components are designed to run remotely and communicate with the primary component via .NET Remoting. The product is currently undergoing a QA cycle, and the QA team had a bizarre issue to report: when the system is configured to run on localhost and the network cable is disconnected while the system is up and running, remoting requests fail (they reported that the primary component fails to notify the satellite component instances to shut down, but it was actually the same with any remote call). My immediate response was "huh?" but subsequent local testing assured me that they weren't smoking anything illegal.
After quite a bit of research (this is a seemingly little-known issue with .NET Remoting) I managed to come some interesting insights into .NET, but only one relevant post I managed to find after playing with Google Groups a bit: apparently when Windows detects a network cable disconnect (via a feature called Media Sense) it "removes the bound protocols from that adapter until it is detected as "up" again". The only workaround I could find was to completely disable Media Sense, which needless to say is a very unwelcome solution.
I suppose the obvious question is "why the hell does Media Sense shut down localhost connections?" I'm often dumbfounded by bizarre design decisions in Microsoft products, but this one may just necessitate adding a really awful hack to our installation procedures on clients' sites, which just sucks.