iptables-save > /root/firewall_rules.backup

For older Linux kernels you have an option of stopping service iptables with service iptables stop but if you are on the new kernel, you just need to wipe out all the policies and allow all traffic through the firewall. This is as good as you are stopping the firewall.

Use below list of commands to do that.
iptables -F
iptables -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT

Where –

-F: Flush all policy chains
-X: Delete user-defined chains
-P INPUT/OUTPUT/FORWARD: Accept specified traffic

Once done, check current firewall policies. It should look like below which means everything is accepted (as good as your firewall is disabled/stopped)
iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination

 Chain FORWARD (policy ACCEPT)
 target     prot opt source               destination

 Chain OUTPUT (policy ACCEPT)
 target     prot opt source               destination