IP Tables
- Allows system administrators to define rules that control how incoming and outgoing traffic is handled
Important commands:
iptables --version - Command to check iptables version
iptables -L - To check the list of input and output traffic
iptables -A INPUT -p tcp -s 172.xx.xxx.xxx --dport 22 -j ACCEPT
- Command permits SSH access only from the given IP(172.xx.xxx.xxx) address. This is a solid approach for limiting SSH access to trusted sources — a common best practice for hardening servers.
-A INPUT: Appends the rule to the INPUT chain, which handles packets destined for the local system.
-p tcp: Specifies that the rule applies to TCP packets.
-s 172.xx.xxx.xxx: Source IP address. Only packets coming from this IP will be matched.
--dport 22: Destination port 22 — typically used for SSH.
-j ACCEPT: The action to take — allow the packet through.
iptables -A INPUT -s 192.168.1.100 -j DROP - Command to drop all incoming traffic from a specific IP
iptables -A OUTPUT -j ACCEPT - To allow all outgoing traffic
