Manually enabling DB2 to use TCP/IP

When you create an instance using db2icrt you may not have the TCP/IP portion automatically enabled.  To enable it type in the following in your DB2 command prompt:

db2set DB2COMM=TCPIP
db2 update dbm cfg using SVCENAME db2c_DB2

Make sure you have the following line in your etc\services file.  The db2c_DB2 corresponds to the one on the update dbm cfg.

db2c_DB2 50000/tcp

Then restart your database instance.  If all goes well you should see

SQL1063N  DB2START processing was successful.

If not you may see

SQL5043N  Support for one or more communications protocols failed to start successfully. However, core database manager functionality started successfully.

I sometimes have to use db2icrt because sometimes my laptop crashes and the DB2 instance gets corrupted to the point that it is no longer recoverable.