Port Check

The port check attempts to connect to an address specified with the --address or -a flag and port specified with the --port or -p flag.

The check can be further refined by using the --timeout or -t flag to customize the connection wait time and the --invert or -i flag to return success when a port is not being listened on. Execute check_port --help for more details.

With --invert set to the default of false, check_port will return OK (exit code of 0) if the address and port connection is successful. Otherwise it will return CRITICAL (exit code 2).

The Nagios metric name defaults to listening_port but can be changed with the --metric_name or -m option.

Listener on Address and Port

$ check_port --address www.google.com --port 443
CheckPort OK - port 443 on www.google.com using tcp | listening_port=0

No Listener on Address and Port

$ check_port --address www.google.com --port 81 --timeout 2
CheckPort CRITICAL - port 81 on www.google.com using tcp (dial tcp 216.58.192.228:81: i/o timeout) | listening_port=2

Inverted No Listener on Address and Port

$ check_port --address www.google.com --port 81 --timeout 2 --invert
CheckPort OK - port 81 on www.google.com using tcp (dial tcp 216.58.192.228:81: i/o timeout) | listening_port=0