RHEL / Centos Linux Disable Firewall

[a] /etc/init.d/iptables – IPv4 iptables firewall service.

[b] /etc/init.d/ip6tables – IPv6 iptables firewall service.

Disable firewall

Type the following command as the root user to disable firewall for IPv4:
# service iptables save
# service iptables stop
# chkconfig iptables off
Sample outputs:

iptables: Flushing firewall rules:                         [  OK  ]
iptables: Setting chains to policy ACCEPT: filter          [  OK  ]
iptables: Unloading modules:                               [  OK  ]

Sample output with verification (see below):

Enable firewall

Type the following command as the root user to enable firewall for IPv4:
# service iptables start
# chkconfig iptables on
Sample outputs:

iptables: Applying firewall rules:                         [  OK  ]

Type the following command as the root user to disable firewall for IPv6 :
# service ip6tables start
# chkconfig ip6tables on

Verify that firewall is disabled

Type the following command as root user to see IPv4 firewall rules:
# /sbin/iptables -L -v -n
OR
# service iptables status
The following output indicates that firewall is not active:

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination

(b)  IPv6

Type the following command as the root user to disable firewall for IPv6 :
# service ip6tables save
# service ip6tables stop
# chkconfig ip6tables off

Type the following command as root user to see IPv6 firewall rules:
# /sbin/ip6tables -L -v -n
OR
# service ip6tables status