Setting the session keep-alive parameter

You can use the TCP keep-live parameter to set the maximum idle time that the TCP protocol allows before sending a probe to test for an inactive session.

The protocol sends keep-alive requests to the remote client any time the session remains idle for periods longer than the keep-alive value. The idle period is defined by the Session keep-alive timeout parameter in Telnet Properties in System i® Navigator, or the TIMMRKTIMO parameter on the CHGTELNA command. When a session appears to be inactive (no response is received from the remote client to any keep-alive probe) that session is ended, the virtual device associated with the session is returned to the free pool of virtual devices, and the IBM® i operating system performs the action set in the QDEVRCYACN system value on the interactive job running on the virtual device. This action affects only named virtual devices. For automatically selected virtual devices (QPADEVxxxx), the interactive job always ends.

The Telnet server defines the keep-alive setting to 600 seconds by default.

This setting takes effect at server startup. In addition to the session keep-alive timeout parameter, you might also want to review the Timeout interval settings in the Inactive Jobs System Values in System i Navigator. Refer to Setting inactive job timeout used by Telnet.

To set the keep-alive parameter for Telnet in System i Navigator, follow these steps:

  1. In System i Navigator, select your system > Network > Servers > TCP/IP.
  2. In the right pane, right-click Telnet and select Properties.
  3. On the Telnet Properties page, click the General tab.
  4. On the Telnet Properties - General page, specify the number of seconds for "Session keep alive timeout" to send a probe to the remote clients for the session keep alive timeout.