TN3270 Server Commands 25
keepalive
keepalive
Use thekeepalive TN3270 configuration command to specify how many seconds of inactivity
elapsebefore transmission of a DO TIMING-MARK to the TN3270 client. Use the no form of this
command to cancel the keepalive period and return to the default.
keepaliveseconds
no keepalive
Syntax Description
Defaults
The default in TN3270 configuration mode is 1800 seconds (30 minutes).
The default in PU configuration mode is the value currently configured in TN3270 configuration
mode.
Command Modes
TN3270 configuration
PU configuration
Usage Guidelines
Thekeepalive command can be entered in either TN3270 configuration mode or PU configuration
mode. A value entered in TN3270 mode applies to all PUs for that TN3270 server, except as
overridden by values entered in PU configuration mode. Ano keepalive command entered in PU
configuration mode will restore thekeepalive value entered in TN3270 command mode.
If the client does not reply within 30 minutes of the transmission of the DO TIMING-MARK, the
TN3270 server disconnects the TN3270 session. The DO TIMING-MARK is a Telnet protocol
operation that does not affect the client operation.
If the IP path to the client is broken, the TCP layer will detect the failure to acknowledge the DO
TIMING-MARK and initiate disconnection. This action will usually take much less than 30
minutes.
Thekeepalive command affects currently active and future TN3270 sessions. Forexample, reducing
thevalue to a smaller nonzero value will cause an immediate burst of DO TIMING-MARKs on those
sessions that have been inactive for a period of time greater than the new, smaller value.
Examples
The following command sets a keepalive disconnect value of 15 minutes (900 seconds):
keepalive 900
Thefollowing command entered in TN3270 configuration mode sets the keepalive disconnect value
to 1800 seconds, the default:
no keepalive
seconds Number of seconds, from 0 to 65535. A value of 0 means
no keepalive signals are sent. The default is 1800 seconds
(30minutes).