Trace port in AIX

AIX Command

1. netstat -Aan | grep
- This shows if the specified is being used. The hex number in the first column is the address of protocol control block (PCB)

2. rmsock tcpcb
- This shows the process who is holding the socket. Note that this command must be run as root.

AIX Example

Let's set SVCENAME to 30542, so that the listener will use this port. Then, use the commands above to check if the port is indeed being used by DB2 LUW.

$ db2 update dbm cfg using svcename 30542
$ db2start
$ netstat -Aan | grep 30542
f10000f303321b58 tcp4 0 0 *.30542 *.* LISTEN

The netstat command, above, shows that the port 30542 is being used for listening. To confirm that it is DB2 LUW that's using the port, run rmsock as root like following.

$ rmsock f10000f303321b58 tcpcb
The socket 0x3321800 is being held by proccess 692476 (db2sysc).

This shows that it's db2sysc process that's using the port, and its PID is 692476.

Note that rmsock, unlike what its name implies, does not remove the socket, if the socket is being used by any process. Instead of removing the socket, it just reports the process holding the socket. Also note that the second argument of rmsock is the protocol. It's tcpcb in the example to indicate that the protocol is TCP.