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CN2668 Routers and Switches

CN2668 Routers and Switches. Kemtis Kunanuraksapong MSIS with Distinction MCTS, MCDST, MCP, A+. Agenda. Chapter 6: Router Startup and Configuration Exercise Quiz. Router Startup. In general, the boot process follows these steps: Test hardware (POST) Load the bootstrap program

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CN2668 Routers and Switches

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  1. CN2668Routers and Switches Kemtis Kunanuraksapong MSIS with Distinction MCTS, MCDST, MCP, A+

  2. Agenda • Chapter 6: Router Startup and Configuration • Exercise • Quiz

  3. Router Startup • In general, the boot process follows these steps: • Test hardware (POST) • Load the bootstrap program • Locate and load the Cisco IOS • Locate and load the router configuration file • See Figure 6-1 on Page 146

  4. Test Hardware (POST) • ROM in a router contains • The power-on self-test (POST) • The bootstrap program • A version of the operating system • During the POST, the ROM Monitor checks the configuration register for instructions regarding how to load the Cisco IOS

  5. Router Configuration Files • startup-config (backup configuration) • The router configuration file that loads during the boot process • To revert to the settings in your startup-config • Reboot the system by powering the router off and back on again • Issue the reload command at the privileged EXEC mode prompt

  6. Router Configuration Files • To view the contents of the startup-config • Type show start-upconfigor show start at the enable prompt • To see your working or running configuration • Type show running-config or just show run at the enable prompt • See command in Table 6-1 on Page 148

  7. Methods for Making Changes • Basic steps to implement changes: • Make changes as desired to the configuration • Examine those changes • Determine if the changes meet the desired result • Remove the changes if they do not meet the desired result, or simply reboot the router • Copy the changes from the running configuration to the startup configuration when they do meet the desired result

  8. IP on the Router • To manually configure IP on an interface • Change to interface configuration mode • Use the ip address command to configure an IP address for the specific interface • To configuring a serial interface as a DCE (data communication equipment) • You will also need to add the clockrate [bandwidth in bits per second] command

  9. Telnet • Utility that connects at the application layer and provides remote access to other devices • Cisco routers allow telnet connections via their virtual terminal ports

  10. IP Host Names • To determine the address to name mapping on your router, type: router#show hosts • To add an entry to your hosts file • Go to global configuration mode and type: router(config)#ip host router15 192.168.5.1 • To remove that entry, type: router(config)#no ip host router15 192.168.5.1 • To allow a name server to handle the IP address to name resolution, type: router(config)#ip name-server 172.33.44.1

  11. Ping and Trace • To verify connectivity at the Internetwork layer of the TCP/IP model • Ping can return the following replies: ! Successful receipt of the ICMP echo . Request timed out U Destination was unreachable C Congestion experienced I Ping interrupted ? Packet type unknown & Packet TTL exceeded

  12. Ping and Trace (continued) • Using the ping command alone • Allows you to enter your ping command step by step ( specify protocol type, size of packet, etc) • Trace sends multiple ICMP packets with progressively higher time-to-live counters (TTL) • Until the packet reaches the destination

  13. Ping and Trace (continued) • The following responses can be returned by a trace: !H Indicates that a router received, but did not forward, the ICMP echo request P Protocol unreachable N Network unreachable U Port unreachable * Request timed out

  14. IP Route • Issue the show ip route command from the enable mode prompt • To display the routing table • Typically, routing tables are dynamically created when routing protocols are configured on the router • If you want, you can use the ip route command from the global configuration mode • To statically enter routes in the routing table

  15. Checking the Interface • show interfaces command • Check the configuration of a specific interface from the enable mode prompt • Example: router#showint s0/0 • Replies • Serial0/0 is up, line protocol is up • Serial0/0 is up, line protocol is down • The interface is up, but no packet received • Serial0/0 is up, line protocol is administratively down • Required no shutdown to bring the interface up • Serial0/0 is down, line protocol is down

  16. Checking the Interface (continued) • Clear counters • The router keeps detailed statistics regarding data passing across its interfaces • To clear the counters for interface f0/0, type: router#clear interface f0/0 • debug command • One of the most powerful tools you can use to obtain information from your router • Tool is only available from privileged EXEC mode

  17. Cisco Discovery Protocol (CDP) • Cisco proprietary Data Link layer protocol • Shares configuration information between Cisco devices that are connected directly to each other • All Cisco devices can use CDP to: • Discover each other • Learn about the configurations of other devices • Using CDP can help you quickly determine the network topology • See Figure 6-4 on Page 155 • CDP was designed to be a low-overhead protocol

  18. Cisco IOS • Cisco IOS is usually loaded from flash memory • If the router cannot find the IOS in flash memory, it will look for a copy on a TFTP server • If it cannot find one there, it will boot a minimal version of the IOS from ROM • If you want to see information about your router’s flash memory: • Type show flash from the enable mode prompt

  19. Configuration Register • Every Cisco router has a 16-bit configuration register, which is stored in NVRAM • This register allows you to control several boot functions: • Forcing the system into the bootstrap program • Enabling or disabling the console Break function • Setting the console terminal baud rate • Loading the IOS from ROM • Loading the IOS from a TFTP server • Examine the configuration register by typing show version

  20. ROM Monitor Mode • The bootstrap program that is built into the firmware of the router • Used to initialize the hardware and load the IOS • To perform other tasks such as diagnostics and recovering passwords • Configure your system to enter ROM Monitor mode • Enter the following command at the global configuration prompt: router(config)#config-register 0x2100

  21. ROM Monitor Mode (continued) • Configure your system to boot a smaller IOS image from ROM and enter RxBoot mode • Enter the following command at the global configuration prompt: router(config)#config-register 0x2101

  22. RxBoot Mode • A limited version of the IOS • Boot into this mode: • When you want to access a TFTP server to download a new IOS • If your router enters RxBoot mode without your intervention • Indicates that the router could not find a good IOS image • Prompt: router(boot)

  23. Boot System Commands • As long as the configuration register is configured with a 2 as the final hexadecimal digit • The ROM Monitor will look for boot system commands in NVRAM during the bootup process • Enable your system to boot an IOS file from the TFTP server • From global configuration mode: router(config)#boot system tftp somefile.bin

  24. Backing Up and Restoring the IOS • copy flash tftp • The command for backing up your IOS to a TFTP server • You will be asked for the source filename, the IP address of the TFTP server, and the destination filename • Type erase flash at the privileged EXEC mode prompt • To erase the IOS

  25. Upgrading the IOS • Before you load a new IOS file to your router • Use the show flash command to ensure there is enough free memory to hold it • The system will tell you how much memory is used and how much is free • If there is not enough memory to hold both the current IOS image and the upgrade • You will have to erase the existing flash memory as previously mentioned

  26. Router Password Recovery • Password recovery • You must be physically connected to the router using the console cable • Steps to perform password recovery on the Cisco 2600 series: • Follow the steps on Page 161 - 162

  27. Security Device Manager • A Web-based tool primarily used for implementing and testing security configurations • To configure routing protocols, WAN services, wireless routing, firewalls, virtual private networks (VPNs), and quality of service (QoS) • SDM is typically not used to configure basic functionality on a Cisco router • See Figure 6-8 on Page 162

  28. Assignment • Review Questions • 1 – 25 • Lab 6.1 – 6.5

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