Oracle XE 12c won't configure - getting the "port 5,500 in use" error message I have the infamous "port 5,500 in use" error message while trying to start/configure Oracle XE 12c.

I have searched for this problem and every solution I have found has been the same - make sure the hostname matches between /etc/hostname and /etc/hosts. I have done that, using grep -w to confirm the strings are the same, and they are, but the problem is not resolved.


/etc/hostname

iv4x.rdu.csb

/etc/hosts

127.0.0.1   iv4x.rdu.csb localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6



The difference I see with the above is I didn't have a non-loopback IP address in /etc/hosts.  I attempted using those addresses reported by "ip a", but all of those failed as well, e.g.:


/etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.122.1   iv4x.rdu.csb



I should add that I have used netstat to search for anything using that port and I found nothing. I have also tried configuring Oracle to use different ports and received the same error message for any port that I tried.

I would appreciate any suggestions, thanks.
I found the solution with the assistance of our DBA team.

The problem was I using a fully qualified hostname in the /etc/hosts file. I had interpreted the solutions I found that cited "hostnames must match" to include the domain name as well.

If your hostname is xxxx.yyyy.zzzz, then you add just "xxxx" to /etc/hosts, per the instructions provided:

127.0.0.1    xxxx.yyyy.zzzz    anything-else   xxxx

In my case, I added just "iv4x" to the loopback line.