The Advanced settings specify which network protocols are used to check computer availability. The two protocols used are ICMP and NetBios. The NetBios request is actually a UDP NetBios datagram sent to a remote host to check if its file sharing service is active and running. If you set the Ping method to Both, the service will first perform an ICMP query and then, if there is no answer, a NetBios query. If there is no response to either query, the computer is assumed to be inactive.