DB2 does not start if the machine name is changed after DB2 is installed

If a machine name is changed post-installation, DB2 fails to start, and produces the following error:
SQL6048N A communication error occurred during START or STOP DATABASE MANAGER processing.
Note that due to retries at establishing communications, Blueworx Voice Response may not produce the error for a considerable period of time (up to 10 minutes).

A TCP/IP communication error occurred while the START or STOP DATABASE MANAGER command was trying to establish connection with all the nodes defined in the sqllib/db2nodes.cfg file.

To resolve this problem, do the following:

  1. Ensure that the node has the proper authorization defined in the .rhosts or the host.equiv files.
  2. Ensure that all the host names defined in the db2nodes.cfg file in the sqllib directory are defined on the network and are running. The format of the entries in db2nodes.cfg is:
    0 hostshortname 0
    For example, for a system called freda.hursley.ibm.com, it would be:
    0 freda 0

    To change a machine name in db2, go to/home/dtdb23in/sqllib, and make the change in the db2nodes.cfg file.