Then (if I remember correctly) every time someone attempts to download the list of servers, we run a code to check which server entries in the list have not been updated during the past 60 seconds, and those are deleted before returning the server list to the one who requested it.
The serverlist template of ANet does it exactly this way. This method is great because it can be done in PHP+SQL without a special program or setting on the server.
A much cleaner solution would be server-side checking for the "connectablility" of the servers.
You could also implement the first methode and let the client (the one who is searching) check if he can connect to the servers in the list. This way you can also get informations about the ping to the server.
