Or in this case when the list server is down.

First, please don't post "Test" messages. Try sending a command to the
listserv (NOT the mailing list...remember it is a different address
"listserv@vanagon.com" not vanagon@vanagon.com.) Normally commands sent to the
listserv will return in only a few minutes (so check for a confirmation on
your command after say, 20 or 30 minutes.) The listserv's are smart enough
that if you are already subscribed, they won't subscribe you a second time. If
you don't get a response (you should always get a response, even if the
command is invalid) then the listserv itself is probably offline.

This is a simple way to check the status of the list serv and it doesn't cause
a couple dozen "Test" messages from everyone who thinks they were suddenly
unsubscribed from the list.