This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
determines when and how this file will be consulted. Added comment to
the effect that (1) zero is not a vaild network number and (2) please
get a valid network number assigned by your provider or by the Internet
Registry.