One of my test servers at my house runs openSUSE 12.1. I like openSUSE and have been a user since the early 90s. It’s still my favorite distro. One thing I noticed when I installed DB2 10.1 on my openSUSE 12.1 server was that I could not connect to the database using Data Studio. I would always get a “connection refused” error. Digging deeper, I found the problem. For some reason, the db2c_db2inst1 entry was missing in /etc/services. Adding the following is necessary should it not be present:

db2c_db2inst1   50000/tcp

This makes the DB2 instance listen on port 50000. It didn’t solve the problem though. I still could not connect remotely to my database. Only after I made sure that the following variable was set, it finally worked.

db2set DB2COMM=tcpip

Again, for no apparent reason, this wasn’t set properly. I haven’t seen this issue on my other servers running RHEL. I hope this helps you, should you discover the same issue and have exhausted all other options of troubleshooting.