Common reasons require you to restart Iptables firewall Service
Iptables is firewall service that comes and distributed within Linux OS. In most cases you need to restart Iptables firewall service if you made changes to iptables firewall config file .
How To Restart Iptables firewall Service under Linux / UNIX
The following examples using the restart command in case you want to stop the service you can use stop command and use start command to start stopped service.
You have run these command under root/administrator privileges .
Restart Iptables firewall on Fedora / RHEL / Red Hat/CentOS Linux version 5.x/6.x
To restart an IPv4 iptables based firewall:
service iptables restart
To restart an IPv6 iptables based firewall:
service ip6tables restart
Restart Iptables firewall on Fedora / RHEL / Red Hat /CentOS Linux version 7.x
To restart an IPv4 iptables based firewall:
systemctl restart iptables.service
To restart an IPv6 iptables based firewall:
systemctl restart ip6tables.service
Start/Stop Iptables Firewall Service On Ubuntu Linux
To Stop Iptables Firewall Service On Ubuntu Linux
sudo service ufw stop
To Start Iptables Firewall Service On Ubuntu Linux
sudo service ufw start
