Tuning TCP/IP

Specify a small value, five minutes or less, for the TCP/IP KeepAlive timer. You can specify the value for the TCP/IP KeepAlive timer either in the TCP/IP KEEPALIVE field of the Distributed data facility panel 2: DSNTIP5 or in the TCPKPALV parameter. If the network fails between the server's reply and the next client request, TCP⁄IP waits until the KeepAlive timer expires, then notifies the DB2 subsystem of the failure.

The server thread hangs while the timer is running. Do not use the timer default of ENABLE because it results in a value of 2 hours, which means that threads can hang for up to 2 hours. A hanging thread can cause unpredictable results, depending on what resources it has locked.

If you are connecting to a location whose LINKNAME is associated with a row in the table SYSIBM.IPNAMES and it has a domain name in the IPADDR field, gethostbyname can return a list of IP addresses associated with the LINKNAME. When trying to connect to this location, DB2 will try each of these IP addresses in a round-robin fashion (starting with the first address) until the connection is successful, or the attempt to connect to each IP address has timed out.