It is good practice to keep iptables/firewall enabled. But configuring it is difficult, do you agree. Not any more 🙂
sudo yum install firewall-config
This will install a GUI application, which you can run with “Firewall” application in the dash or with “firewall-config” in terminal. It is pretty straight forward to use this tool, even if you don’t have much knowledge on Firewall/iptables.
Last couple of years, I just used to disable iptables on my system, this time I decided not to disable it and keep it enabled.
So far so good, now comes the tricky part, I have http server enabled on my system and since this is on local network with already firewall and other security in place so I can allow all incoming to my system and similarly I need to enable XDMCP outgoing. So, I can add the rules like this :
iptables -A INPUT -p tcp –dport 22 -j ACCEPT
iptables -A OUTPUT -p udp -s 0/0 -d 0/0 --dport 177 -j ACCEPT for XDMCP
This works only till I reboot my system and is not persistent. Okay, so I can put this in rc.local file. But why I should do that, there should be more elegnant way. So, I searched and finally found that I can simply put the rules in /etc/sysconfig/iptables as follows:
-A INPUT -p tcp –dport 22 -j ACCEPT
-A OUTPUT -p udp -s 0/0 -d 0/0 --dport 177 -j ACCEPT for XDMCP