Remote port

The probe checks accessibility of a remote port.

Settings example

Field Description


Protocol of the checked port, TCP or UDP.


IP address or DNS name of the remote host to check.


The port to check.


Additional test data which can be sent to remote port while the check is performing.


Maximum time to perform the check in milliseconds.


How often to perform the check (60 seconds by default).


After the check has been done result is displayed in the Data table:

Field Description


Check result:

  • true - the port is accessible;

  • false - the port is not accessible.


Messages about the check errors or port inaccessibility reasons.

Command-line utility

This check is the counterpart of the terminal command netcat:

$ netcat -zv 80
Connection to 80 port [tcp/http] succeeded!

$ netcat -zvu 80
Connection to 80 port [udp/http] succeeded!

Known problems and errors

Sensor error! [net.sf.oval.ConstraintViolation: must be between 1 and 65535 inclusive]

Specified Port value is out of the valid range from 1 to 65535.

Check the correctness of the data in the field Port.

messageError - UnknownHostException:

The specified Hostname is not found (getaddrinfo: Name or service not known).

Probable reasons:

  • the specified hostname is incorrect;

  • the specified hostname is not available from the network, where the check was performed;

  • the specified hostname contains "http://" or "https://" protocol prefix.

Check the correctness of the specified hostname.

Check the availability of the specified hostname, performing the command netcat on the terminal, where the agent is installed.

Do not specify prefixes in the field Hostname.