when you want to 'ping' an IP do you mean like any internet site, QB64.org, Google, Yahoo. facebook, ect.. or do you mean a networked computer or user to see if they are still connected, for like a game or program? For the former I don't think I can help but for the latter this is what I usually put in my code,
for the host side:
IF NumClients
> 0 THEN 'only bother if there are clients FOR I
= 1 TO NumClients
' distribute PING message to all clients Users(I).PingTime = UpTime&
LastPing = UpTime&
and the client side:
'inside a loop-----
'---------------------
Response%% = TRUE
and once the host sends the ping the client has a certain amount of time to reply or is considered 'disconnected' or lost. and gets removed from the client array.
I think if you can use one of the QB64 commands to have a similar result with online sites, but not sure as I have never played with it. Luke used to have a bot in the IRC chat room that would pull from Wikipedia the same process could probably be used to check whether a site was up or not based on a time out. but not sure there of course.