[apache2] Configure apache to listen on port other than 80

It was a firewall issue. There was a hardware firewall that was blocking access to almost all ports. (Turning off software firewall / SELinux bla bla had no effect)

Then I scanned the open ports and used the port that was open.

If you are facing the same problem, Run the following command

sudo nmap -T Aggressive -A -v 127.0.0.1 -p 1-65000

It will scan for all the open ports on your system. Any port that is open can be accessed from outside.

Ref.: http://www.go2linux.org/which_service_or_program_is_listening_on_port