chapter 2 ccna

chapter 2 ccna.. MOP (Operations and Maintenance Protocol): provides TFTP-like functionality in a DecNET environment..CDP: Cisco-specific protocol used to share basic hardware and software information with connected Cisco devices. If the interface is connected to a device that is not a Cisco device or is not trusted, disable CDP on the interface.NTP: Disable NTP on the interface if the interface should not receive NTP messages. be sure to use a combination of NTP when implementing NTPand authentication (this is discussed in Chapter 17) . Directed Broadcast: in IOS 12.0 and later. directed broadcast is disabled by default.. Free ARP: Most routers send ARP whenever a client connects to it over a PPP link and negotiates IP addressing information; a hacker can use this to launch an ARP poisoning attack that fills up the router's ARP table.. Interfaces: IOS switches enable all interfaces by default. Cisco recommends that unused interfaces be disabled.15.3.2 AutoSecureThe problem with manually disabling unused services is that you must manually configure the individual commands. AutoSecure is an IOS functionChapter 15 Router Initial Configuration 369feature that was originally used on Cisco ISR routers, such as the 870, 1800, 2800, and 3800 series routers, to allow you to provide basic security configuration by running a simple script. This feature was later introduced in IOS 12.3 and 12.3T. This is a privileged EXEC script, similar to a system configuration dialog: the system configuration dialog creates the basic configuration for the router, while AutoSecure is used only to configure the security features that protect the router. Like the System Configuration Dialog script, AutoSecure asks some basic questions about how to protect the router. It automatically enables or disables services on the router; establishes a stateful firewall by configuring Context-BasedAccessControl (CBAC), which requires the I0S image to provide security; configures access control lists (ACLs are discussed in Chapter 21), and performs other tasks.