PingFirst and PingLast are unique as a way to reduce polling overhead and increasing performance. If you specify PingFirst, then the ping test will run before any other tests for that particular device. If the ping test passes, the other tests are run. If the ping fails, the other tests do not run. PingLast does the opposite. If at least one of the other tests passes for a device, the PingLast test will not run, as you know the device is reachable. If all other tests fail, then it will run.| Protocol | What is sent to the server | What is expected in reply |
| http | GET / HTTP/1.1 Host: ip_address:port Connection: close | HTTP/1.1 200 OK |
| ftp | QUIT | 221 |
| smtp | HELO | 250 |
| dns | DNS lookup | DNS reply |