DB2 Version 9.7 for Linux, UNIX, and Windows
DB2 Version 9.7 for Linux, UNIX, and Windows
NAT helps alleviate the inevitable shortage of available IPv4 addresses. It is seen as a quick-fix alternative to the IPv6 solution (which may take decades to implement). NAT is supported in an HADR environment.
HADR always cross checks local and remote host configurations on the primary and standby nodes.
In a NAT environment, a host is known to itself by one IP address, but known to the other hosts by a different IP address. This behavior will cause the HADR host cross check to fail.
To avoid this situation in a NAT environment, you can set registry variable DB2_HADR_NO_IP_CHECK to ON. This will bypass the host cross-check, enabling the primary and standby to connect in a NAT environment.
It is recommended to leave the DB2_HADR_NO_IP_CHECK registry variable OFF, the default setting, if you are not running in a NAT environment. Disabling the cross check weakens HADR's validation of your configuration.