Bash Script for some handy iptable commands

Main Categories

1. Policies

  a. Deny by Default
  b. Accept by Default

2. Specific Attacks Prevention

  a. Ping Flood  
  b. TCP SYN Flood  
  c. Malformed Packets  
  d. Smurf Attacks

3. Worst Case Options

  a. Block all incoming traffic  
  b. Flush all rules

4. Backup / Restore

  a. Backup current rules
  b. Restore from backup

Introduction

I wanted to create a script to help enhance my understanding of cyber security concepts and to learn more about iptables.

Improvements To be Made

1. More Specific Attacks
2. Add other handy iptables commands (Initial Setup, etc..)
3. Add IPv6 conversion as currently it is only for IPv4

Optimizations to keep in mind

1. Place loopback / forwarding rules as early as possible
2. Use state / connection tracking modules to bypass fire wall for established connections
3. Combine rules to standard TCP clientserver connections to single rule w/ port list heavy traffic servers rules as early as possible

Sources

1. https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands
2. https://www.crybit.com/how-to-save-current-iptables-rules/
3. https://www.digitalocean.com/community/tutorials/how-to-list-and-delete-iptables-firewall-rules#:~:text=To%20flush%20a%20specific%20chain,sudo%20iptables%20%2DF%20INPUT
4. https://linuxhint.com/how_to_use_ip_tables_to_block_icmp/