Setup

1. Edit the Script in Notepad and customize it to your liking, everything is explained.
2. Upload the Script to a anywhere the root/sudo can access. (/etc would be the best folder)
3. Make sure the file is executable, run "chmod +x /locationofthefile/iptables.rules.sh
4. Run the Script. (/locationofthefile/iptables.rules.sh)
5. Run the following command: iptables-save > /etc/iptables.up.rules
6. You will have to make sure the IPTables are set at System Reboot.

This step will depend on your Linux Distro

Debian

1. Enter the command; nano /etc/network/if-pre-up.d/iptables
2. Add the following lines to it and make the file executable.

#######!/bin/bash ######/sbin/iptables-restore < /etc/iptables.up.rules

Make the file executable by using; chmod +x /etc/network/if-pre-up.d/iptables

Ubuntu

1. Enter the command; nano /etc/network/interfaces
2. Add a single line (shown below) just after ‘iface lo inet loopback’:

pre-up iptables-restore < /etc/iptables.up.rules

Other Distros

I'm afraid I can't help you here, you'll have to google your way out of this one!

FAQ/Issues

Please make sure you've followed the instructions first! If you're 100% certain that you have, here's a few questions I expect.

Errors

• -bash: /filelocationhere/iptables.rules.sh: /bin/sh^M: bad interpreter: No such file or direct

The file was saved in a DOS Format, it needs to be Unix.

1. vi /filelocationhere/iptables.rules.sh
2. Press Shift + :
3. Write: %s/^M//g (To get the ^M, Hold Ctrl while pressing V and M
4. Press Shift + :
5. Write: wq

• bash: /filelocationhere/iptables.rules.sh: Permission denied

Ahah, gotcha! You didn't follow the instructions fully.

chmod +x /filelocationhere/iptables.rules.sh

FAQ

• Is it safe to make changes?

Yes, you can safely make changes. When you're done, execute the script and then do "iptables-save > /etc/iptables.up.rules"

• Where do the Logs get saved?

You can view the logs in: /var/logs/messages Easiest way to find Invalid Packets/Flood is to search for either;

Invalid Packets Dropped: Valid Packets (Flood) Dropped:

• SRC= The source ip-address from where the packet originated
• DST= The destination ip-address where the packet was sent to
• LEN= Length of the packet
• PROTO= Indicates the protocol. (UDP in this case)
• SPT= Indicates the source port.
• DPT= Indicates the destination port.