Resolving port 5500 not free issue during Oracle 12c Release 2 Database Configuration Assistant installation on CentOS Background

I am attempting to install Oracle 12c on CentOS 7 (deployed as a Hyper-V virtual machine) as outlined by this installation guide.

Problem

Everything with my installation goes well except for the Oracle Database Configuration Assistant.

The installation provides me with the following messages:


ACTION: Specify a free port
Action - Refer to the logs or contact Oracle Support Services.


Debuging Information and Actions Attempted

When I run a tail on the error log I get the following messages related to the installation:

INFO: ... GenericInternalPlugIn: getting configAssistantParmas.
INFO: ... GenericInternalPlugIn: checking secretArguments.
INFO: ... GenericInternalPlugIn: starting read loop.
INFO: Read: [FATAL] [DBT-06103] The port (5,500) is already in use.
INFO: [FATAL] [DBT-06103] The port (5,500) is already in use.
WARNING: Skipping line: [FATAL] [DBT-06103] The port (5,500) is already in use.
INFO: Read:    ACTION: Specify a free port.
INFO:    ACTION: Specify a free port.
WARNING: Skipping line:    ACTION: Specify a free port.
INFO: Completed Plugin named: Oracle Database Configuration Assistant


Running sudo netstat -anp | grep 550 returns the results below:

unix  3      [ ]         STREAM     CONNECTED     37299    5502/gnome-pty-help
unix  3      [ ]         STREAM     CONNECTED     37283    5501/gconfd-2
unix  3      [ ]         STREAM     CONNECTED     37287    5501/gconfd-2


To try and remedy the problem, prior to subsequent fresh installation attempts I commented out the following statements in my services file as displayed through running cat /etc/services | grep 550

new-rwho        550/tcp                 # new-who
new-rwho        550/udp                 # new-who
3m-image-lm     1550/tcp                # Image Storage license manager 3M Company
3m-image-lm     1550/udp                # Image Storage license manager 3M Company
ads             2550/tcp                # ADS
ads             2550/udp                # ADS
ssmpp           3550/tcp                # Secure SMPP
ssmpp           3550/udp                # Secure SMPP
gds-adppiw-db   4550/tcp                # Perman I Interbase Server
gds-adppiw-db   4550/udp                # Perman I Interbase Server
#fcp-addr-srvr1  5500/tcp                # fcp-addr-srvr1
#fcp-addr-srvr1  5500/udp                # fcp-addr-srvr1
#fcp-addr-srvr2  5501/tcp                # fcp-addr-srvr2
#fcp-addr-srvr2  5501/udp                # fcp-addr-srvr2
#fcp-srvr-inst1  5502/tcp                # fcp-srvr-inst1
#fcp-srvr-inst1  5502/udp                # fcp-srvr-inst1
#fcp-srvr-inst2  5503/tcp                # fcp-srvr-inst2
#fcp-srvr-inst2  5503/udp                # fcp-srvr-inst2
#fcp-cics-gw1    5504/tcp                # fcp-cics-gw1
#fcp-cics-gw1    5504/udp                # fcp-cics-gw1
checkoutdb      5505/tcp                # Checkout Database
checkoutdb      5505/udp                # Checkout Database
amc             5506/tcp                # Amcom Mobile Connect
amc             5506/udp                # Amcom Mobile Connect
fg-sysupdate    6550/tcp                # fg-sysupdate
fg-sysupdate    6550/udp                # fg-sysupdate
cloudsignaling  7550/udp                # Cloud Signaling Service


I have additionally attempted to do step 5.1 of the installation guide prior to the installation with no success.

Screenshot



Question

Why am I getting an error that the port isn't open when it doesn't seem like anything is using that port and how to I remedy this issue?

Is there are method that can be used to change the port from 5500 to a complete different one? I'm just trying to get a dummy database installed for the HR schema.
I encountered this exact error and found it was my mistake. Spent whole day for that.

Please, carefully observe your /etc/hostname and /etc/hosts.
In my case, "oem" was put in /etc/hosts and "eom" was in /etc/hostname.