| Summary

| This module covered techniques to control access to the router, switch, and the network by managing access at the console ports and terminal lines, as well as setting up passwords, accounts and privilege levels. For security purposes, network devices should be configured to only support the traffic and protocols the network needs. In addition to disabling certain network services in the interest of greater security, administrators should be able to filter packets using Access Control Lists (ACLs) on inbound and outbound traffic. By carefully constructing ACLs, it is possible for a network administrator to reduce many types of network attacks. Network Address Translation (NAT) can also be used to separate a LAN from an untrusted network. Also, specific security configurations available on access layer switches, including the port security, VLANs, monitoring, and switch specific access-lists can be implemented.

Careful management and thorough audits of router and switch operations are also necessary to reduce network downtime, improve security, and aid in the analysis of suspected security breaches. Event logging, authoritative time source processes, and adequate software and configuration maintenance are examples of network management tasks that should be performed. Furthermore, administrators should use SSH when managing routers, switches and other key network devices in order to protect passwords and sensitive data.