Understanding iptables in Linux

Aim:

Learn about iptables in Linux and how to use it to control incoming and outgoing network traffic.

What is iptables?

Iptables is a user-space utility program that allows a system administrator to configure IP packet filter rules in the Linux kernel firewall, implemented as different Netfilter modules. It is a powerful tool for managing network security by defining rules for packet filtering, network address translation (NAT), and other packet mangling operations.

Blocking Incoming Packets for a Port

Block incoming packets for a specific port (e.g., port 80):
```
sudo iptables -A INPUT -p tcp --dport 80 -j DROP
```

Blocking Outgoing Packets for a Port

Block outgoing packets for a specific port (e.g., port 443):
```
sudo iptables -A OUTPUT -p tcp --dport 443 -j DROP
```

Blocking Tomcat Port Using iptables

Assuming Tomcat is running on port 8080, block incoming packets for the Tomcat port:
```
sudo iptables -A INPUT -p tcp --dport 8080 -j DROP
```

Verification:

View the current iptables rules:

sudo iptables -L

Written by: A.M.Rinas

Contact: mohomadrinas00@gmail.com

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