firewall

Here’s firewall configuration RHEL 6 and below

Check the status for reboot persistance

chkconfig –list | grep iptables

Command to add the firewall to accept traffic with port 22 on source 192.1.1.2

iptables -I INPUT 2 -p tcp –dport 22 -s 192.1.1.2 -j ACCEPT

Default location of iptables files 

/etc/sysconfig/iptables

Location of iptables configuration file

/etc/sysconfig/iptables-config

Stop & Start the iptables service

service iptables stop

service iptables start 

List all the iptables

service iptables status 

OR

iptables -L

Add iptables rule

iptables -A INPUT -p tcp -s 0.0.0.0./0 -m tcp –dport 20301 -j ACCEPT

Drop iptables rule

iptables -D INPUT -p tcp -s 0.0.0.0/0 -m tcp –dport 20301 -j DROP

Save the currently running iptables to the file and system

service iptables save (It automatically overwrites it to the /etc/sysconfig/iptables)

If you edited the iptable file and want to save it use

iptables-restore < /etc/sysconfig/iptables

If you edited the iptables via commands and want to save it

service iptables save