First create a ipfilters firewall file. Call it ipfilter.firewall.rules for example. Here’s an example: http://library.linode.com/securing-your-server#sph_creating-a-firewall
- -A means append the rule to the end of the table with the table specified, such as INPUT.
- -j means perform this action on matching the rule, REJECT for example.
- -i specifies the interface to listen on.
- -d specifies the destination including the network mask.
- –dport specifies the destination port
- -p specifies the protocol, such as tcp
You can then set it as your firewall like so:
iptables-restore < iptables.firewall.rules
Then you can list all the added rules via