A new TPF Operations Server (TOS) option for the hardware management console (HMC) interface has been created to prevent a network firewall from dropping the TOS HMC connection.

The TOS HMC interface is used as a tertiary console for z/TPF in case both 3215 primary and fallback consoles fail. During normal operation, the TOS HMC session receives very little or no network traffic, however, if a network firewall is set up between the HMC and the TOS server, any idle TCP sessions will be dropped without informing both ends. At that point, the TOS HMC session needs to restart.  

APAR IT34114 prevents the TOS HMC sessions from being disconnected abnormally by firewall software. The keep-alive packets will be exchanged to make the session active. The TOS administrator can configure how long the keep-alive packet is exchanged by specifying the TOS server option called Inactivity Keep Alive Timer. If this option is omitted, the keep-alive packets will be exchanged every 5 minutes. The TOS HMC interface is built and packaged with the latest z15 HMC library and DLL, which improves the session connectivity.

For more detail about IT34114, see the APEDIT.