Test with UDP sends 10 echo request packets to the specified host (on port 7/udp). It then shows the round-trip time for each response, or an error if the echo isn't received. The results window also displays number of packets sent so far, packets received and lost (not returned), and minimum, average, and maximum round-trip times for the test. Note: round-trip times aren't highly accurate - they're affected by machine activity. The results window also has an Again button to repeat the test, and a Continuous checkbox, which will repeat the test constantly until the box is unchecked or the window is closed. This is useful for testing problems over time. If Control is down when the UDP test is started, the Continuous checkbox will be turned on automatically. A UDP echo daemon is one of Interarchy's Safe Daemons.
Test with ICMP looks the same as Test via UDP, but uses lower level ICMP echo packets instead of UDP echoes. ICMP echoes are generally handled by OS-level networking software (Open Transport or MacTCP in Mac OS), and thus work even when Interarchy's Safe Daemons setting is off.