Describe the responsibilities of the IOS. The Cisco router IOS software is responsible for network protocols and providing supporting functions, connecting high-speed traffic between devices, adding security to control access and prevent unauthorized network use, providing scalability for ease of network growth and redundancy, and supplying network reliability for connecting to network resources.
List the options available to connect to a Cisco device for management purposes. The three options available are the console port, auxiliary port, and in-band communication, such as Telnet, SSH,
and HTTP. Don’t forget, a Telnet connection is not possible until an IP address has been configured and a Telnet password has been configured.
Understand the boot sequence of a router. When you first bring up a Cisco router, it will ru n a power-on self-test (POST), and if that passes, it will look for and load the Cisco IOS from flash memory, if a file is present. The IOS then proceeds to load and looks for a valid configuration in NVRAM called the startup-config. If no file is present in NVRAM, the router will go into setup mode.
Describe the use of setup mode. Setup mode is automatically started if a router boots and no startup-config is in NVRAM. You can also bring up setup mode by typing setup from privileged mode. Setup provides a minimum amount of configuration in an easy format for someone who does not understand how to configure a Cisco router from the command line.
Differentiate user, privileged, and global configuration modes, both visually and from a command capabilities perspective. User mode, indicated by the routername> prompt, provides a command-line interface with very few av ailable commands by default. User mode does not allow the configuration to be viewed or changed. Privileged mode, indicated by the routername# prompt, allows a user to both view and change the configuration of a router. You can enter privileged mode by typing the command enable andentering the enable password or enable secret password, if set. Global configuration mode, indicated by the routername(config)# prompt,
allows configuration changes to be made that apply to the entire router (as opposed to a configuration change that might affect only one interface, for example).
Recognize additional prompts available in other modes and describe their use. Additional modes are reached via the global configuration prompt, routername(config)# , and their prompts include interface, router(config-if)# , for making interface settings; line configuration mode, router(config-line)# , used to set passwords and make other settings to various connection methods; and routing protocol modes for various routing protocols; router(config-router)# ,
used to enable and configure routing protocols.
Access and utilize editing and help features. Make use of typing a question mark at the end of commands for help in using the commands. Additionally, understand how to filter command help with the same question mark and letters. Use the command history to retrieve commands previously utilized without retyping. Understand the meaning of the caret when an incorrect command is rejected. Finally, identify useful hot key combinations.
Identify the information provided by the show version command. The show version command will provide basic configuration for the system hardware as well as the software version, the names and sources of configuration files, the configuration register setting, and the boot images.
Set the hostname of a router. The command sequence to set the hostname of a router is as follows:
Differentiate the enable password and enable secret password. Both of these passwords are used to gain access into privileged mode. However, the enable secret password is newer and is always encrypted by default. Also, if you set the enable password and then set the enable secret, only the enable secret will be used.Describe the configuration and use of banners. Banners provide information to users accessing the device and can be displayed at various login prompts. They are configured with the banner command and a keyword describing the specific type of banner.
Set the enable secret on a router. To set the enable secret, you use the global config command enable secret . Do not use enable secret password password or you will set your password to password password . Here is an example:
enable secret tod
Set the console password on a router. To set the console password, use the following sequence:
line console 0
Set the Telnet password on a router. To set the Telnet password, the sequence is as follows:
line vty 0 4
Describe the advantages of using Secure Shell and list its requirements. Secure Shell (SSH) uses encrypted keys to send data so that usernames and passwords are not sent in the clear. It requires that a hostname and domain name be configured and that encryption keys be generated.
Describe the process of preparing an interface for use. To use an interface, you must configure it with an IP address and subnet mask in the same subnet of the hosts that will be connecting to the switch that is connected to that interface. It also must be enabled with the no shutdown command. A serial interface that is connected back to
back with another router serial interface must also be configured with a clock rate on the DCE end of the serial cable.
Understand how to troubleshoot a serial link problem. If you type show interface serial 0/0 and see down, line protocol is down , this will be considered a Physical layer problem. If you see it as up, line protocol is down , then you have a Data Link layer problem.
Understand how to verify your router with the show interfaces command . If you type show interfaces , you can view the statistics for
the interfaces on the router, verify whether the interfaces are shut down, and see the IP address of each interface.
Describe how to view, edit, delete, and save a configuration. The show running-config command is used to view the current
configuration being used by the router. The show startup-config command displays the last configuration that was saved and is the one that will be used at next startup. The copy running-config startup- config command is used to save changes made to the running configuration in NVRAM. The erase startup-config command deletes the saved configuration and will result in the invocation of the setup menu when the router is rebooted because there will be no configuration present.