Disabling unused ports and interfaces.
Securing administrative access.
Router hardening means that the router is secured against attacks as best as possible. Router hardening is one among the three areas of router security that must be maintained to secure an edge router at the network perimeter. Basically, router hardening secures from tough-to-crack passwords, to the shutting down of unnecessary interfaces, ports, and services. Look for any unused router interfaces and disable them by issuing the shutdown command. Disabling unused services typically include BOOTP, CDP, FTP, TFTP, PAD, and a few others. You can also disable administrative and management protocols currently not being like HTTP or HTTPS, DNS, and SNMP.