DB2 not appearing to listen

During my recent travails with WebSphere Portal and Lotus Forms Server, I hit a problem whereby DB2 UDB was installed and started, but didn't appear to be listening on any TCP/IP ports.

After some digging, I found that DB2 was not correctly set up to automatically listen, despite having the relevant entries in /etc/services.

In summary, I needed to ensure that I had the following: -

DB2_db2inst1 60000/tcp

DB2_db2inst1_1 60001/tcp

DB2_db2inst1_2 60002/tcp

DB2_db2inst1_END 60003/tcp

in /etc/services ( I'm using the 6000x port range but this could easily be another range such
as 5000x etc. ).

Having done this, I then needed to run the following three commands ( as the DB2 instance owner, db2inst1 ): -

DB2 UPDATE DATABASE MANAGER CONFIGURATION USING SVCENAME DB2_db2inst1

DB2SET DB2COMM=TCPIP

DB2START

( note that the first command uses the service name that's listed in /etc/services and may vary
from installation to installation )

Once I updated the DBM configuration and set the DB2 environment variable, all appeared to
be well.