The iptables command is used to configure firewall rules in Linux.To allow packets from a specific source (192.168.10.22) to the server, we must append a rule to the INPUT chain:
iptables -A INPUT -s 192.168.10.22 -j ACCEPT
* Explanation of the command:
* -A INPUT # Appends a rule to the INPUT chain (incoming traffic).
* -s 192.168.10.22 # Specifies the source IP address.
* -j ACCEPT # Accepts the packet and allows communication.
* Why the other options are incorrect?
* A. iptables -L -s 192.168.10.22 -j ACCEPT # Incorrect, -L is used to list rules, not to add them.
* B. iptables -D INPUT -s 192.168.10.22 -j ACCEPT # Incorrect, -D is used to delete a rule, not add one.
* D. iptables -A OUTPUT -S 192.168.10.22 -j ACCEPT # Incorrect, -A OUTPUT affects outgoing packets, but we need to accept incoming packets.
Persisting the Rule:
To make the rule persistent after a reboot, it must be saved:
iptables-save > /etc/iptables/rules.v4
References:
* CompTIA Linux+ Official Documentation
* iptables Documentation - Netfilter