By default the port 80 for http connection is filtered on Redhat 7 as you can only access this port from the actual localhost and not from any other public host. To open a port 80 on RHEL 7 Linux we need to add an iptables rule. For this RHEL7 uses firewall-cmd. First add your port 80 rule with a following command:
[root@rhel7 ~]# firewall-cmd --zone=public --add-port=80/tcp --permanent
Once you add the above firewall rule reload firewall service:
[root@rhel7 ~]# firewall-cmd --reload
And check whether the port was added to ipatables rules:
[root@rhel7 ~]# iptables-save | grep 80
-A IN_public_allow -p tcp -m tcp --dport 80 -m conntrack --ctstate NEW -j ACCEPT
Open http port 80 firewall rule on RHEL7 linux httpd
If you decide to block/remove http port 80 firewall rule you can again use the firewall-cmd command:
[root@rhel7 ~]# iptables-save | grep 80
-A IN_public_allow -p tcp -m tcp --dport 80 -m conntrack --ctstate NEW -j ACCEPT
[root@rhel7 ~]# firewall-cmd --zone=public --remove-port=80/tcp --permanent
success
[root@rhel7 ~]# firewall-cmd --reload
success
[root@rhel7 ~]# iptables-save | grep 80
[root@rhel7 ~]# 
Block/Remove http port 80 firewall rule on RHEL7 linux httpd