Identifying the source IP address of a Db2 requester

In most cases, to configure Db2 for z/OS outbound remote communications that use TCP/IP with other DRDA servers, you do not need to know the source IP address of the Db2 requester, which is chosen by the TCP/IP stack. However, you do need to know the source IP address that is chosen by the TCP/IP stack of a Db2 requester in the following situations:

• When the DRDA servers that are being targeted by that Db2 requester have implemented trusted context definitions
• When the DRDA servers that are being targeted by that Db2 requester have implemented system monitoring profiles that are dependent on the remote location's IP address

Note that the IP address and domain name that Db2 displays when it is started is not the IP address that will be used as a source IP address from this Db2 requester. When an application requests that an outbound TCP connection be established with a remote server at a specific IP address, the TCP/IP stack will provide the source IP address of the connection.

TCP/IP uses an established sequence to select the source IP address for outbound requests. For an explanation of this sequence and to determine how to identify the source IP address of a Db2 for z/OS requester, see How TCP/IP selects a source IP address.

For outbound TCP/IP communications that originate from a Db2 for z/OS requester, the selection sequence employed by the TCP/IP stack starts at step 6.