Port number in use

[Ed Hon]

I have a problem starting an app, because of error "port number already in use". How can I see a list of port numbers allocated and in use? Thanks.

[Rita C Workman]

Try using lsof utility for something like this. You can download from:

http://hpux.cs.utah.edu/hppd/hpux/Sysadmin/lsof-4.51/

/rcw

[John Bolene]

You can also use netstat -a|grep xxx
where xxx is the port in question.

[rick jones]

I will _guess_ that you will find old connections from the last instantiation o fthe app - stuff in TIME_WAIT, FIN_WAIT_2, perhaps other states. So long as there is nothing for that port number in the LISTEN state it implies there is a bug in the app - it is not setting SO_REUSEADDR before attempting to bind() to its well-known port number.

[Philip Chan_1 · Accepted solution]

netstat -a|grep EST, would give you the connection couples that were established.

The lsof command (optional) should be able to tell you which process have these ports open.

~Philip