Router Startup and Config.


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Router Startup and Config.

  1. 1. CCNA Guide to Cisco Networking <ul><li>Chapter 7: Router Startup and Configuration </li></ul>
  2. 2. Objectives <ul><li>Understand router startup </li></ul><ul><li>Describe and use the Cisco Discovery Protocol </li></ul><ul><li>Understand configuration management commands for Cisco routers and the 1900 series switch </li></ul><ul><li>Configure IP on the Cisco router and the 1900 series switch </li></ul><ul><li>Troubleshoot router connectivity problems </li></ul>
  3. 3. Router Startup <ul><li>Boot process steps </li></ul><ul><li>Test hardware </li></ul><ul><li>Load bootstrap program </li></ul><ul><li>Locate and load the Cisco IOS </li></ul><ul><li>Locate and load the router configuration file </li></ul>
  4. 4. Router Startup (continued)
  5. 5. Router Startup (continued) <ul><li>POST </li></ul><ul><ul><li>Power-on self test (POST) </li></ul></ul><ul><ul><ul><li>Bootstrap program </li></ul></ul></ul><ul><ul><ul><li>Diagnostic test for hardware </li></ul></ul></ul><ul><ul><ul><li>ROM monitor </li></ul></ul></ul><ul><ul><li>Read-only memory (ROM) </li></ul></ul>
  6. 6. Router Startup (continued) <ul><li>Configuration register </li></ul><ul><ul><li>16-bit setting stored in NVRAM </li></ul></ul><ul><ul><ul><li>Hexadecimal code </li></ul></ul></ul><ul><ul><li>Configuration register controls several boot functions </li></ul></ul><ul><ul><ul><li>Forcing the system into the bootstrap program </li></ul></ul></ul><ul><ul><ul><li>Enabling or disabling the console Break function </li></ul></ul></ul><ul><ul><ul><li>Setting the console terminal baud rate </li></ul></ul></ul><ul><ul><ul><li>Loading the IOS from ROM </li></ul></ul></ul><ul><ul><ul><li>Loading the IOS from a TFTP server </li></ul></ul></ul><ul><ul><li>“ show version” command </li></ul></ul>
  7. 7. Router Startup (continued)
  8. 8. Router Startup (continued)
  9. 9. Router Startup (continued) <ul><li>ROM monitor mode </li></ul><ul><ul><li>(>) or (rommon>) </li></ul></ul><ul><ul><li>ROM monitor mode initiates when </li></ul></ul><ul><ul><ul><li>Manually configured </li></ul></ul></ul><ul><ul><ul><li>Cannot locate Cisco IOS </li></ul></ul></ul><ul><ul><ul><li>A forced system break </li></ul></ul></ul><ul><ul><li>Ctrl+”break” keys with in 60 seconds (Hyperterm) </li></ul></ul><ul><ul><li>“ config-register 0x2100” command </li></ul></ul><ul><ul><ul><li>“ show version” command </li></ul></ul></ul><ul><ul><ul><li>“ copy run start” command </li></ul></ul></ul><ul><ul><ul><li>“ reload” command </li></ul></ul></ul>
  10. 10. Router Startup (continued) <ul><li>RxBoot mode </li></ul><ul><ul><li>Cannot boot from flash </li></ul></ul><ul><ul><li>Cannot locate IOS or corrupt IOS </li></ul></ul><ul><ul><li>RxBoot mode prompt </li></ul></ul><ul><ul><ul><li>Router hostname followed by (boot) </li></ul></ul></ul><ul><ul><ul><li>Router(boot) </li></ul></ul></ul><ul><ul><li>Limited set of IOS commands to configure the router </li></ul></ul>
  11. 11. Router Startup (continued) <ul><li>Cisco IOS </li></ul><ul><ul><li>Usually loaded from flash memory </li></ul></ul><ul><ul><li>“ show flash” command </li></ul></ul><ul><ul><li>“ show version” command </li></ul></ul><ul><ul><li>Fallback options for loading the IOS </li></ul></ul><ul><ul><ul><li>Load from TFTP server </li></ul></ul></ul><ul><ul><ul><li>Cannot find IOS, load from ROM (basic IOS) </li></ul></ul></ul><ul><ul><li>Default fallback sequence to locate the IOS </li></ul></ul><ul><ul><ul><li>Flash </li></ul></ul></ul><ul><ul><ul><li>TFTP server </li></ul></ul></ul><ul><ul><ul><li>ROM </li></ul></ul></ul>
  12. 12. Router Startup (continued)
  13. 13. Router Startup (continued)
  14. 14. Boot System Commands <ul><li>Alternative to the “config-register” command </li></ul><ul><li>Configure router to locate IOS </li></ul><ul><li>Boot system commands are stored in start-up configuration file </li></ul><ul><li>Boot system commands only work when last digit of config-register is “2” </li></ul><ul><li>Boot system command structure </li></ul><ul><ul><li>“ boot system [location of IOS] [IOS file name]” </li></ul></ul><ul><ul><li>“ boot system tftp c1700-j-mz.122-5(t).bin” </li></ul></ul>
  15. 15. Boot System Commands <ul><li>Router will broadcast looking for a tftp a computer running TFTP software </li></ul><ul><li>TFTP server must be on a subnet directly connected to the router broadcasting for TFTP services </li></ul><ul><li>Multiple “boot system” commands maybe entered for redundancy </li></ul><ul><li>“copy run start” command </li></ul>
  16. 16. Upgrading The IOS <ul><li>Upgrading IOS check list </li></ul><ul><ul><li>Ensure router has enough memory </li></ul></ul><ul><ul><ul><li>“show flash” command </li></ul></ul></ul><ul><ul><li>Backup current IOS to a TFTP server </li></ul></ul><ul><ul><ul><li>Identify the current IOS file name </li></ul></ul></ul><ul><ul><ul><li>“show flash” command </li></ul></ul></ul><ul><ul><ul><li>“show version” command </li></ul></ul></ul><ul><li>“copy tftp flash” command </li></ul>
  17. 17. Router Configuration Files <ul><li>Startup-config file </li></ul><ul><ul><li>Also known as the backup configuration file </li></ul></ul><ul><li>Startup-config file is loaded into RAM at which point it becomes the running-config file </li></ul><ul><li>“ show startup-config” command </li></ul><ul><li>Reboot the system to revert to the settings is the startup-config file </li></ul><ul><ul><li>Power off and on </li></ul></ul><ul><ul><li>“ reload” command </li></ul></ul>
  18. 18. Router Configuration Files (continued) <ul><li>“copy start run” or “copy tftp run” merges with the current running-config settings </li></ul><ul><li>No “erase running-config” command </li></ul><ul><li>“erase startup” command </li></ul><ul><ul><li>Not the same as “erase nvram” </li></ul></ul>
  19. 19. Methods For Making Changes <ul><li>Changes can be implemented and tested without saving to the startup-config file </li></ul><ul><li>Changes to the running configuration take place immediately </li></ul><ul><li>Basic steps for implementing changes </li></ul><ul><ul><li>Make desired changes </li></ul></ul><ul><ul><li>Examine the changes and the affects </li></ul></ul><ul><ul><li>Determine if the changes meet the desired results </li></ul></ul><ul><ul><li>Remove changes if they do not meet the desired results or simply reboot the system </li></ul></ul><ul><ul><li>If desired result have been met then save to startup-config file </li></ul></ul>
  20. 20. CDP <ul><li>Cisco discovery protocol (CDP) </li></ul><ul><li>Proprietary Data Link layer protocol </li></ul><ul><li>Shares basic system and configuration settings to directly connected Cisco devices </li></ul><ul><ul><li>Routers </li></ul></ul><ul><ul><li>Switches </li></ul></ul><ul><ul><li>Hubs </li></ul></ul><ul><ul><li>Access servers </li></ul></ul>
  21. 21. CDP (continued) <ul><li>“ show cdp neighbors” command provides the following options </li></ul><ul><ul><li>Ethernet </li></ul></ul><ul><ul><ul><li>Learn about Ethernet interfaces attached to neighbors </li></ul></ul></ul><ul><ul><li>Null </li></ul></ul><ul><ul><ul><li>Learn about interfaces of a neighbor that does not have an address assigned </li></ul></ul></ul><ul><ul><li>Serial </li></ul></ul><ul><ul><ul><li>Information about neighbors connected to serial interfaces </li></ul></ul></ul><ul><ul><li>Detail </li></ul></ul><ul><ul><ul><li>Detailed information about the CDP neighbor and all attached devices </li></ul></ul></ul><ul><ul><ul><li>This detailed information includes device identification, remote interface type, and remote IP address </li></ul></ul></ul>
  22. 22. CDP (continued) <ul><li>Low-overhead protocol </li></ul><ul><li>Broadcasts information ever 60 seconds by default </li></ul><ul><li>Enabled on all Cisco devices by default </li></ul><ul><li>Possible to turn off CDP </li></ul><ul><ul><li>Entire router </li></ul></ul><ul><ul><li>Individual interfaces </li></ul></ul>
  23. 23. IP On The Router <ul><li>IP maybe configured by the extended setup program </li></ul><ul><li>Steps to manually configure IP on the router and the interface </li></ul><ul><ul><li>Enter global configuration mode </li></ul></ul><ul><ul><li>“ ip routing” command </li></ul></ul><ul><ul><li>Enter interface mode for desired interface </li></ul></ul><ul><ul><li>Assign IP address </li></ul></ul><ul><ul><li>Activate the interface </li></ul></ul><ul><ul><ul><li>“ no shutdown” command </li></ul></ul></ul>
  24. 24. IP On The Router (continued) <ul><li>Two ways to have multiple IPs on an interface </li></ul><ul><ul><li>Secondary IP address </li></ul></ul><ul><ul><li>Subinterfaces </li></ul></ul><ul><li>“term ip netmask-format” command </li></ul>
  25. 25. IP On The Switch <ul><li>IP address are not required on a switch </li></ul><ul><li>Switches operate on the Data Link layer (MAC) addresses </li></ul><ul><li>To remotely manage a switch assign </li></ul><ul><ul><li>IP address for the entire switch </li></ul></ul><ul><ul><li>Assign a gateway for the switch </li></ul></ul><ul><li>By default switches are not configured with an IP address or a gateway </li></ul>
  26. 26. IP Connectivity
  27. 27. Telnet <ul><li>Connects at the highest layer of the OSI model </li></ul><ul><li>Provides remote access </li></ul><ul><li>Virtual terminal ports </li></ul><ul><li>Successful telnet connection means connectivity at all layers </li></ul>
  28. 28. IP Host Names <ul><li>Refer to a remote host or router by name </li></ul><ul><li>Address to name mapping on the router </li></ul><ul><li>“ip host router_central” </li></ul><ul><li>“show hosts” command </li></ul><ul><li>“ip host” command is local service </li></ul><ul><li>DNS is a non-local name resolution service </li></ul>
  29. 29. IP Host Names (continued) <ul><li>DNS is a non-local name resolution service </li></ul><ul><li>“ip name-server” </li></ul>
  30. 30. Ping And Trace <ul><li>Test Internetwork layer connectivity of the TCP/IP model </li></ul><ul><li>Available in User EXEC and Privileged EXEC modes </li></ul><ul><li>ICMP </li></ul><ul><ul><li>Echo request </li></ul></ul><ul><ul><li>Echo reply </li></ul></ul><ul><li>“ping” command and extended mode ping </li></ul><ul><li>“traceroute” command </li></ul>
  31. 31. Ping And Trace (continued) <ul><li>Ping utility send five packets and will have the following replies </li></ul><ul><ul><li>!: Successful receipt of the ICMP echo </li></ul></ul><ul><ul><li>.: Request timed out </li></ul></ul><ul><ul><li>U: Destination was unreachable </li></ul></ul><ul><ul><li>C: Congestion experienced </li></ul></ul><ul><ul><li>I: Ping interrupted </li></ul></ul><ul><ul><li>?: Packet type unknown </li></ul></ul><ul><ul><li>&: Packet TTL exceeded </li></ul></ul>
  32. 32. Ping And Trace (continued) <ul><li>Traceroute responses </li></ul><ul><ul><li>!H: Indicates that a router received, but didn’t forward, the ICMP echo request </li></ul></ul><ul><ul><li>P: Protocol unreachable </li></ul></ul><ul><ul><li>N: Network unreachable </li></ul></ul><ul><ul><li>U: Port unreachable </li></ul></ul><ul><ul><li>*: Request timed out </li></ul></ul>
  33. 33. IP Route <ul><li>If ping or traceroute fail check the routing table </li></ul><ul><li>“show ip route” command </li></ul><ul><ul><li>Displays the routing table </li></ul></ul><ul><ul><li>Routing table displays </li></ul></ul><ul><ul><ul><li>Directly connected networks </li></ul></ul></ul><ul><ul><ul><li>Dynamically learned networks </li></ul></ul></ul><ul><ul><ul><li>Statically assigned routes </li></ul></ul></ul>
  34. 34. Checking The Interface <ul><li>If the interface is down then packets cannot be delivered </li></ul><ul><li>“ show interface” command </li></ul><ul><ul><li>Check the status of the interface </li></ul></ul><ul><ul><li>View the interface configuration </li></ul></ul><ul><li>Possible interface states </li></ul><ul><ul><li>Serial0/0 is up, line protocol is up </li></ul></ul><ul><ul><li>Serial0/0 is up, line protocol is down </li></ul></ul><ul><ul><li>Serial0/0 is down, line protocol is down </li></ul></ul><ul><ul><li>Serial0/0 is administratively down, line protocol is down </li></ul></ul>
  35. 35. Checking The Interface (continued) <ul><li>Clear counters </li></ul><ul><ul><li>Routers keep detail statistics (counters) </li></ul></ul><ul><ul><li>Sometimes beneficial to clear the existing counters </li></ul></ul><ul><ul><li>“ clear interface serial 0/0” </li></ul></ul><ul><li>Debug </li></ul><ul><ul><li>Debugs provides information on real-time router events </li></ul></ul><ul><ul><li>Resource intensive </li></ul></ul><ul><ul><ul><li>Negative impact on router performance </li></ul></ul></ul><ul><ul><ul><li>Do not run for extended periods of time </li></ul></ul></ul><ul><li>“ no debug all”, “undebug all” </li></ul>
  36. 36. Router Password Recovery <ul><li>Password recovery is not the same for all router and switch modules </li></ul><ul><li> has instructions available for every Cisco network device </li></ul><ul><li>Cannot perform password recovery through telnet or other remote means </li></ul><ul><li>Password recovery example (2600 series router) </li></ul><ul><ul><li>Connect to router via console connection </li></ul></ul>
  37. 37. Router Password Recovery (continued) <ul><li>Password recovery example (2600 series router) (continued) </li></ul><ul><ul><li>Connect to router via console connection </li></ul></ul><ul><ul><li>Power cycle the router (cold boot) </li></ul></ul><ul><ul><li>Enter break sequence within 60 seconds of boot </li></ul></ul><ul><ul><ul><li>Hyperterm (Ctrl+break), Tera Term (ALT+b) </li></ul></ul></ul><ul><ul><li>At rommon> prompt type “confreg 0x2142” </li></ul></ul><ul><ul><li>Enter the “reset” command to reboot the router </li></ul></ul><ul><ul><li>Do not enter setup sequence </li></ul></ul><ul><ul><li>“ copy start run” command </li></ul></ul>
  38. 38. Router Password Recovery (continued) <ul><li>Password recovery example (2600 series router) (continued) </li></ul><ul><ul><li>Change passwords </li></ul></ul><ul><ul><li>“config-register 0x2102” command to reset router </li></ul></ul><ul><ul><li>“copy run start” command </li></ul></ul>
  39. 39. Summary <ul><li>When the router boots, it follows a set routine </li></ul><ul><li>Although the router’s boot process can vary, the typical boot process follows this sequence: </li></ul><ul><ul><li>First, the router checks all of its internal hardware components during a process called the POST (power-on self-test) </li></ul></ul><ul><ul><li>Next, the router loads the basic configuration routine known as the bootstrap program </li></ul></ul><ul><ul><li>Then, the bootstrap attempts to locate the Cisco IOS, which in turn loads the router configuration file </li></ul></ul>
  40. 40. Summary (continued) <ul><li>If the Cisco IOS is set to load from a TFTP server, but the TFTP server cannot be located, then the IOS will boot from flash memory </li></ul><ul><li>If the IOS cannot be found in flash memory or on the TFTP server, then a limited version will boot from ROM </li></ul><ul><li>If the Cisco IOS is set to load a configuration file from a TFTP server, but the file or server is not available, the configuration file will be loaded from NVRAM </li></ul><ul><li>However, if a configuration file is not available in NVRAM or on a TFTP server, then the automated setup routine will be initialized </li></ul>
  41. 41. Summary (continued) <ul><li>The Cisco Discovery Protocol (CDP) is proprietary to Cisco devices </li></ul><ul><li>This protocol shares information between Cisco devices about other local Cisco devices </li></ul><ul><li>CDP uses broadcasts to update neighbors every 60 seconds by default (the update time interval is configurable) </li></ul><ul><li>Devices share information about their interface configurations and connections to other devices </li></ul><ul><li>IP configuration on Cisco switches and routers is similar: the command syntax is ip address [IP address] [subnet mask] </li></ul>
  42. 42. Summary (continued) <ul><li>When you configure an address for a router interface, you must be in interface configuration mode (config-if ) </li></ul><ul><li>When you configure an IP address for a Catalyst 1900 switch, you need only be in global configuration mode </li></ul><ul><li>These switches don’t require IP addresses; you need only configure one if you intend to remotely manage the switch </li></ul><ul><li>You can verify router connectivity to other systems by using telnet to determine if there is Application layer connectivity </li></ul>
  43. 43. Summary (continued) <ul><li>If you cannot get connectivity at the Application layer, try trace and ping </li></ul><ul><li>Then, check your routing table with the show ip route command to determine if there is a problem with the Network layer </li></ul><ul><li>One of the most important troubleshooting commands is the show interfaces command </li></ul><ul><li>If your interfaces are not up, you cannot route packets </li></ul>