Close monitor connections

Last published : Sep 24, 2026
The NetScaler appliance sends probes to the services through the monitors bound to the services. By default, the monitor on the appliance and the physical server follow the complete handshake procedure even for monitor probes. However, this procedure adds overhead to the monitoring process and might not be always necessary.
For the TCP type monitor, you can configure the appliance to close a monitor-probe connection after receiving SYN-ACK from the service. To do so, set the value of the monitorConnectionClose parameter to RESET. If you want the monitor-probe connection to go through the complete procedure, set the value to FIN.
Note: The monitorConnectionClose setting is applicable only for type TCP and TCP-Default monitors.
To configure monitor-connection closure by using the command line interface:
At the command prompt, type:
set lb parameter -monitorConnectionClose <monitor_conn_close_option>
Example
set lb parameter -monitorConnectionClose RESET
To configure monitor-connection closure by using the configuration utility:
  1. Navigate to Traffic Management > Load Balancing > Configure Load Balancing Parameters.
  2. Select FIN or Reset.

Closing Monitor Connections at the Service or Service Group Level

You can also configure the appliance to close a monitor-probe connection at the service and service group level by setting the monConnectionClose parameter. If this parameter is not set, the monitor connection is closed by using the value set in the global load balancing parameters. If this parameter is set at the service or service group level, the monitor connection is closed by sending a connection termination message, with the FIN or RESET bit set, to the service or service group.

To configure monitor-connection closure at the service level by using the CLI

At the command prompt, type:
set service <service_name> -monConnectionClose ( RESET | FIN )

To configure monitor-connection closure at the service group level by using the CLI

At the command prompt, type:
set serviceGroup <service_name> -monConnectionClose ( RESET | FIN )

To configure monitor-connection closure at the service level by using the GUI

  1. Navigate to Traffic Management > Load Balancing > Services.
  2. Add or edit a service, and in Basic Settings, set the Monitoring Connection Close Bit.

To configure monitor-connection closure at the service group level by using the GUI

  1. Navigate to Traffic Management > Load Balancing > Service Groups.
  2. Add or edit a service group, and in Basic Settings, set the Monitoring Connection Close Bit.
Note: For closing a monitor-probe connection using global load balancing parameters, you can configure monitorConnectionClose to FIN or RESET. When you configure the monitorConnectionClose parameter to;
  • FIN: The appliance performs a complete TCP handshake.
  • RESET: The appliance closes the connection after receiving the SYN-ACK from the service.
In the lighter version of NetScaler CPX, the monitorConnectionClose parameter value is set to RESET by default and cannot be changed to FIN at the global level. However, you can change the monitorConnectionClose parameter to FIN at the service level.