Telnetting to port 3700 (the DB2 listener in your case) will only give you a partial connection, not a telnet login prompt. Typically you will see a message that you can use <CTRL> ] to escape.
If you get this far then it means that the DB2 listener is "listening" correctly on the port, so your bit is done.
Using telnet in this way is a sure way of determining if your services and inetd.conf files are set up correctly and connections are possible. If a DB2 client connection doesn't work correctly the it possibly points to an incorrect config line in the inetd.conf file.
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