How Do I Disable Firewall in Linux?

First login as the root user.

Next enter the following three commands to disable firewall.
# service iptables save
# service iptables stop
# chkconfig iptables off

iptables is administration tool / command for IPv4 packet filtering and NAT. You need to use the following tools:

[a] service is a command to run a System V init script. It is use to save / stop / start firewall service.

[b] chkconfig command is used to update and queries runlevel information for system service. It is a system tool for maintaining the /etc/rc*.d hierarchy. Use this tool to disable firewall service at boot time.