I am not sure what you are asking, but I have come across the expression in two areas:
1. Distributed servers (look for Nagios for example)
2. Applications servers (check out Trend Micro Office application)
In the first case the "master" server monitors (checks) the other servers in the distributed network.
In the second case the host is running an AV product and checks clients that try to log into the apps server to see that their AV product is up to date and running.
I am afraid you need to be a bit more specific in your question.
OH! another thought I am sure I have heard the term used in an internet gaming context?
EDIT: I have just seen your other thread. I think that the gaming example is closest. The server is checking something before connecting you. In a commercial environment that could be the workgroup authorised to the server, the workstation ID, MAC address or whatever. In gaming it would check that there was room for you to play. In MS Access you can get the host to check (restrict) the number of users of the database at any one time.