Intermediate LevelLinux Commands & SysAdmin
How do UFW and iptables configure Linux packet filtering firewall rules?
❓ Interview Prompt: Explain Linux firewalling, Netfilter architecture, iptables chains (INPUT, OUTPUT, FORWARD), tables (filter, nat), and UFW CLI wrappers.
Linux kernel packet filtering is driven by Netfilter:
1. iptables:
Defines explicit rules across chains:
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INPUT: Packets addressed to local server.
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OUTPUT: Locally generated outgoing packets.
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FORWARD: Packets routed through server.
2. UFW (Uncomplicated Firewall):
Simplified CLI wrapper for iptables (e.g. 'sudo ufw allow 22/tcp', 'sudo ufw enable').
Code Implementation Example
bash
# Allow SSH and HTTPS ports using UFW
sudo ufw allow 22/tcp
sudo ufw allow 443/tcp
sudo ufw enable
# Native iptables rule blocking IP address
sudo iptables -A INPUT -s 192.168.1.105 -j DROP💡Configuring network packet filtering rules using UFW and iptables.
🎯 Interview Key Takeaway
Use UFW for straightforward host firewall configuration, and native iptables for complex NAT or packet routing rules.
#iptables#UFW#Firewall#Security#Intermediate
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