TLDRBins TLDRBins / Firewall (Linux)

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Check Firewall Rules

# Show all rules
sudo iptables -L -v -n --line-numbers

Sample Output:
TO-DO
# Show target chain
sudo iptables -L <CHAIN> -v -n --line-numbers

Sample Output:
sudo iptables -L INPUT -v -n --line-numbers

Set Firewall Rules

# Default policy
sudo iptables -P <CHAIN> <RULE>

Sample Output:
sudo iptables -P INPUT DROP

sudo iptables -A <CHAIN> -p <PROTOCOL> -s <SOURCE> --dport <PORT> -j <RULE>

Sample Output:
# Allow SSH from a specific subnet
sudo iptables -A INPUT -p tcp -s 192.168.1.0/24 --dport 22 -j ACCEPT

Delete a Firewall Rule

sudo iptables -D <CHAIN> <LINE_NUMBER>

Sample Output:
TO-DO
sudo iptables -D INPUT 1

Sample Output:
TO-DO