The correct answer is iptables -L, which lists all current firewall rules set by iptables, including those that pertain to the default port for SSH traffic (port 22). It's important to inspect these rules when SSH traffic is being blocked, as a misconfigured or overly restrictive rule might prevent inbound connections. ifconfig is used for configuring network interfaces, not for checking firewall rules. The netstat command is used to display network connections, listening ports, and routing tables, but it doesn’t provide information about firewall rules. nmap is a network scanner and while it can show which ports are open, it does not display actual firewall rules.