The firewall on Redhat 7 Linux system is enabled by default. Normally there should not be a need to disable firewall but it may be quite handy for testing purposes etc. On Redhat 7 Linux system the firewall run as firewalld daemon. Bellow command can be used to check the firewall status:
[root@rhel7 ~]# systemctl status firewalld
firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)
   Active: active (running) since Thu 2014-09-04 19:18:47 EST; 3 months 28 days ago
 Main PID: 539 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─539 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Sep 04 19:18:45 rhel7 systemd[1]: Starting firewalld - dynamic firewall daemon...
Sep 04 19:18:47 rhel7 systemd[1]: Started firewalld - dynamic firewall daemon.
From the above output we can see that the firewall is enabled, which means it will start automatically after reboot and that is also current active. Furthermore, or you can even check all currently applied rules with:
[root@rhel7 ~]# iptables-save

Stop and Start RHEL7 firewall

The firewall on Redhat 7 Linux system can be stopped by a following command:
[root@rhel7 ~]# service firewalld stop
Redirecting to /bin/systemctl stop  firewalld.service
Stopped firewall will start again after system's reboot. To start firewall on Redhat 7 Linux system use:
[root@rhel7 ~]# service firewalld start
Redirecting to /bin/systemctl start  firewalld.service

Disable and Enable RHEL7 firewall

In order to completely disable RHEL7 firewall so it would no load after reboot run:
[root@rhel7 ~]# systemctl disable firewalld
rm '/etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service'
rm '/etc/systemd/system/basic.target.wants/firewalld.service'
Now the firewall would not start after system's reboot. To enable the firewall again run:
[root@rhel7 ~]# systemctl enable firewalld
ln -s '/usr/lib/systemd/system/firewalld.service' '/etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service'
ln -s '/usr/lib/systemd/system/firewalld.service' '/etc/systemd/system/basic.target.wants/firewalld.service'