I discovered recently that Windows 7 (probably other versions too) shows no longer "localhost", but the computer name (with domain), when resolving the IP address 127.0.0.1 or ::1.
The strange thing is, that this still occurs, if I add this mapping explicitly to the hosts file, e.g.
127.0.0.1 localhost
If I use any other name, e.g. "localhostv4", the name is used. Only "localhost" is replaced by the computer name.
Does anyone know why this is happen, and since when? We discovered it recently because we had some functionality depending on it and got a bug report recently and traced it down to this behaviour.