I appreciate all inputs. I recently found out what you all meant by "open" the port. The answer lies in iptables (specifics of which: https://superuser.com/questions/634469/need-iptables-rule-to-accept-all-incoming-traffic )
Also for external clients to access the server, one has to change the /etc/hosts file to establish the server name -> IP mapping.
This article was really helpful to me as someone who does not know basics of networking (http://computernetworkingnotes.com/network-administration/how-to-configure-apache-server-in-linux.html) . It gives a step by step process of setting up an apache server.
Thanks again!