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  1. 1. Configuring and testing CCNA Exploration Semester 1 – Chapter 11
  2. 2. Topics <ul><li>The Internetwork Operating System (IOS). </li></ul><ul><li>Devices that have the IOS embedded. </li></ul><ul><li>IOS commands available to a device. </li></ul><ul><li>IOS modes of operation. </li></ul><ul><li>Basic IOS commands. </li></ul><ul><li>Basic show commands. </li></ul><ul><li>Configuration files </li></ul>
  3. 3. Internetwork Operating System <ul><li>Most Cisco devices use the Cisco IOS. </li></ul><ul><li>Details vary with the device and feature set. </li></ul><ul><li>Normal access through a command line. </li></ul><ul><li>Stored in flash memory and can be upgraded. </li></ul><ul><li>Usually copied into RAM when the device is powered on, and run from RAM. </li></ul>
  4. 4. Access to the interface <ul><li>Console port via serial connection </li></ul><ul><ul><li>Initial configuration </li></ul></ul><ul><ul><li>Disaster recovery </li></ul></ul><ul><ul><li>When network access has failed </li></ul></ul><ul><ul><li>Password recovery </li></ul></ul><ul><ul><li>As well as general management </li></ul></ul><ul><li>Console access does not require a password. Configure a password. Lock the door. </li></ul>
  5. 5. Telnet, SSH, Aux <ul><li>Later management can be via Telnet </li></ul><ul><li>There must be an IP address on the port </li></ul><ul><li>A password must be configured </li></ul><ul><li>Secure shell gives better security </li></ul><ul><li>AUX port can be used locally or via modem but by default does not show error messages </li></ul>
  6. 6. Configuration files <ul><li>Hold the commands that have been configured on the router to customise it. </li></ul><ul><li>Running configuration in RAM holds commands that are in current use </li></ul><ul><li>Startup configuration in NVRAM holds saved commands. These are kept when the power is off and usually copied back into RAM when the router is re-started. </li></ul>
  7. 7. Router storage areas <ul><li>ROM </li></ul><ul><li>Permanent </li></ul><ul><li>Holds POST, boot instructions, basic IOS </li></ul><ul><li>Flash </li></ul><ul><li>Keeps contents </li></ul><ul><li>Holds IOS image </li></ul><ul><li>NVRAM </li></ul><ul><li>Keeps contents </li></ul><ul><li>Holds startup configuration file </li></ul><ul><li>RAM </li></ul><ul><li>Volatile </li></ul><ul><li>Holds runnning config, tables, queues etc </li></ul>
  8. 8. Router IOS modes User EXEC mode Privileged EXEC mode enable disable + password Global Configuration mode Configure terminal Exit or Ctrl+z Specific Configuration modes Exit End Various commands
  9. 9. Router prompts User EXEC mode Privileged EXEC mode Global Configuration mode Specific Configuration modes Router> Router# Router(config)# Router(config-if)# and others
  10. 10. EXEC modes <ul><li>You log in to User EXEC mode Router> </li></ul><ul><li>You can give basic monitoring commands but cannot change the configuration </li></ul><ul><li>Enter enable to go to Privileged EXEC mode Router# </li></ul><ul><li>Password may be used for security </li></ul><ul><li>You can give more commands and can go to configuration modes </li></ul>
  11. 11. Configuration modes <ul><li>Start in privileged EXEC mode and enter the configure terminal (config t) command Router# config t Router(config)# </li></ul><ul><li>The prompt changes </li></ul><ul><li>This is global configuration mode </li></ul><ul><li>Additional commands take you to interface configuration, router configuration etc. </li></ul>
  12. 12. Leaving configuration modes <ul><li>From interface configuration mode there are several ways of getting to privileged EXEC </li></ul><ul><li>Router(config-if)# exit Router(config)# exit Router# </li></ul><ul><li>Router(config-if)# end Router# </li></ul><ul><li>Router(config-if)# Ctrl+z Router# </li></ul>
  13. 13. Command Structure Followed by <Enter>
  14. 14. ? To get help <ul><li>? Gives a list of commands available from the current prompt. </li></ul><ul><li>Command followed by space then ? Gives a list of keywords or arguments that can be used. </li></ul><ul><li>Start of command followed by ? with no space shows how the word can be continued. </li></ul>
  15. 15. Shortened commands <ul><li>Router# show running-config </li></ul><ul><li>Router# show run </li></ul><ul><li>Router# sh ru </li></ul><ul><li>It needs enough letters of each word to be unambiguous. (Tab key shows whole word) </li></ul><ul><li>Router# s ru </li></ul><ul><li>% Ambiguous command: ‘s’ </li></ul>
  16. 16. Other error messages <ul><li>Switch# clock set </li></ul><ul><li>% Incomplete command </li></ul><ul><li>Switch# clock set 19:50:00 25 6 </li></ul><ul><li>% Invalid input detected at ‘^’ marker </li></ul><ul><li>Router# show runming-config </li></ul><ul><li>% Invalid input detected at ‘^’ marker </li></ul>^ ^
  17. 17. Keyboard shortcuts <ul><li>Tab completes a partial command </li></ul><ul><li>Backspace erases to left of cursor </li></ul><ul><li>Ctrl+D erases at cursor (Delete does not) </li></ul><ul><li>Ctrl+Z returns from any config mode to privileged exec mode </li></ul><ul><li>Ctrl+C leave Setup mode </li></ul>
  18. 18. Show commands <ul><li>Show ? To get a list </li></ul><ul><li>Many different show commands to give information about every aspect of the router and its operation </li></ul><ul><li>We use some of the most common. </li></ul>
  19. 19. General show commands <ul><li>Show running-config shows the configuration file from RAM </li></ul><ul><li>Show startup-config shows the saved configuration file from NVRAM </li></ul><ul><li>Show version gives information about the IOS and the router itself. It shows the configuration register, which controls how the router starts up. </li></ul>
  20. 20. Show interfaces <ul><li>Gives statistics for all interfaces </li></ul><ul><li>In particular, says if the interface is up and if the protocol is up – important in troubleshooting. </li></ul><ul><li>Show interfaces serial 0/0 to show one selected interface </li></ul><ul><li>You can shorten to show int s 0/0 </li></ul><ul><li>Show ip interfaces gives IP statistics </li></ul>
  21. 21. Save configuration <ul><li>Router# copy running-config startup-config </li></ul><ul><li>Router# copy run start (shortened) </li></ul><ul><li>Router# wr (Old fashioned, short for write, but it works and is safe.) </li></ul><ul><li>Beware! A typing error in the copy command can delete the operating system. If you get an odd message about Flash – hands off – call for help. </li></ul>
  22. 22. Hostname <ul><li>Router> enable </li></ul><ul><li>Router# config t </li></ul><ul><li>Router(config)# hostname Paris </li></ul><ul><li>Paris(config)# </li></ul><ul><li>Configure a suitable hostname so that you know which router you are managing and so that you can identify it in network documentation. </li></ul>
  23. 23. Console password <ul><li>Paris(config)# line con 0 </li></ul><ul><li>Paris(config-line)# password cisco </li></ul><ul><li>Paris(config-line)# login </li></ul><ul><li>Paris(config-line)# exit </li></ul><ul><li>Restricts access via the console </li></ul><ul><li>Use cisco as the password in labs. </li></ul><ul><li>Use a proper strong password on production networks </li></ul>
  24. 24. Vty password for Telnet <ul><li>Paris(config)# line vty 0 4 </li></ul><ul><li>Paris(config-line)# password cisco </li></ul><ul><li>Paris(config-line)# login </li></ul><ul><li>Paris(config-line)# exit </li></ul><ul><li>Allows and restricts access via 5 vty lines </li></ul><ul><li>Use cisco as the password in labs. </li></ul><ul><li>Use a proper strong, different password on production networks </li></ul>
  25. 25. Enable and enable secret <ul><li>Paris(config)# enable secret class </li></ul><ul><li>The password class is needed when you type enable to enter privileged exec mode </li></ul><ul><li>This password is encrypted </li></ul><ul><li>Paris(config)# enable password cisco </li></ul><ul><li>Not encrypted, used on older routers </li></ul><ul><li>If you configure both, then only the enable secret is used. </li></ul>
  26. 26. Message of the day <ul><li>Paris(config)# banner motd # No unauthorised access # </li></ul><ul><li># is a delimiter to show where the message starts and ends. </li></ul><ul><li>Any character can be used as long as it does not appear in the message. </li></ul><ul><li>The message should make it clear that unauthorised access is forbidden. </li></ul>
  27. 27. Reload <ul><li>Shuts down the router and then starts it again. </li></ul><ul><li>If the configuration has changed then you are prompted to save it. </li></ul><ul><li>The running configuration in RAM is lost. </li></ul><ul><li>The startup configuration from NVRAM is (usually) loaded into RAM on startup. </li></ul>
  28. 28. Back up to TFTP server <ul><li>Start TFTP server software on host </li></ul><ul><li>Paris# copy running-config tftp </li></ul><ul><li>Remote host []? </li></ul><ul><li>Name of configuration file to write [Paris-config]? Paris12Oct07 </li></ul><ul><li>Write file Paris12Oct07 to [confirm] y </li></ul><ul><li>Writing Paris12Oct07 ! ! ! ! ! ! [OK] </li></ul>
  29. 29. Back up as text file <ul><li>Start text capture </li></ul><ul><li>Name file </li></ul><ul><li>show run </li></ul><ul><li>Stop text capture </li></ul><ul><li>Open saved file and </li></ul>
  30. 30. TeraTerm text file <ul><li>TeraTerm is an open source Telnet client. </li></ul><ul><li>It can also act as a SSH client </li></ul><ul><li>It can capture text and save it as a file. </li></ul>
  31. 31. Erase startup configuration <ul><li>Paris# erase NVRAM:startup-config </li></ul><ul><li>Paris# erase startup-config </li></ul><ul><li>Paris# erase start </li></ul><ul><li>If you reload, then the router starts up with the default configuration. No passwords, no IP addresses etc. </li></ul><ul><li>Caution if you get this command wrong then you could erase something else, e.g. IOS </li></ul>
  32. 32. Restore file from TFTP server <ul><li>Router# copy tftp running-config </li></ul><ul><li>You will be prompted for IP address and file name. </li></ul><ul><li>Configuration is copied into RAM and takes effect at once. </li></ul><ul><li>Save to NVRAM. </li></ul>
  33. 33. Restore text file <ul><li>Go to global configuration mode </li></ul><ul><li>Hyperterminal Transfer menu </li></ul><ul><li>Send text file… </li></ul><ul><li>Or </li></ul><ul><li>Copy text from text file </li></ul><ul><li>“ Paste to host” into Hyperterminal session </li></ul>
  34. 34. Configure a router interface <ul><li>Paris(config)# interface FastEthernet 0/0 </li></ul><ul><li>Paris(config-if)# ip address </li></ul><ul><li>Paris(config-if)# no shutdown </li></ul><ul><li>Paris(config-if)# exit </li></ul><ul><li>Interface names vary, depending on whether the router is modular and on the bandwidth. </li></ul><ul><li>E.g. interface Ethernet 0 on an older router </li></ul>
  35. 35. Configure a router interface <ul><li>Paris(config)# interface serial 0/0 </li></ul><ul><li>Paris(config-if)# ip address </li></ul><ul><li>(Paris(config-if)# clock rate 64000 ) </li></ul><ul><li>Paris(config-if)# no shutdown </li></ul><ul><li>Paris(config-if)# exit </li></ul>DCE only
  36. 36. Description <ul><li>Paris(config)# interface fa0/0 </li></ul><ul><li>Paris(config-if)# description Connects to Paris central switch </li></ul><ul><li>Can include circuit and contact information </li></ul><ul><li>Not needed for the operation of the router </li></ul><ul><li>Valuable for documentation as it is included in the configuration listing </li></ul>
  37. 37. Switch interfaces <ul><li>Switch physical interfaces do not have IP addresses </li></ul><ul><li>They are active by default and do not need the no shutdown command. </li></ul><ul><li>It can be useful to give them a description. </li></ul>
  38. 38. Switch IP address <ul><li>The switch IP address goes on a virtual interface, not a real one, normally VLAN1. </li></ul><ul><li>SwA(config)# interface VLAN1 </li></ul><ul><li>SwA(config-if)# ip address </li></ul><ul><li>SwA(config-if)# no shutdown </li></ul><ul><li>SwA(config-if)# exit </li></ul>
  39. 39. Switch default gateway <ul><li>SwA(config)# ip default gateway </li></ul><ul><li>Just like a workstation, a switch needs a default gateway if it exchanges messages with devices on a different network. </li></ul><ul><li>The default gateway is the address of the local router. </li></ul>
  40. 40. Interface – show commands <ul><li>show interfaces states whether up or down, gives some protocol information and statistics about interface use. </li></ul><ul><li>show ip interface gives IP addresses and much more. </li></ul><ul><li>show ip interface brief gives summary of IP addresses and whether up/down. Very useful command. </li></ul>
  41. 41. Up or down <ul><li>Interface status: Layer 1 </li></ul><ul><ul><li>Up </li></ul></ul><ul><ul><li>Down </li></ul></ul><ul><ul><li>Administratively down (no shutdown to bring up) </li></ul></ul><ul><li>Protocol: Layer 2 </li></ul><ul><ul><li>Up </li></ul></ul><ul><ul><li>Down (no keepalive signal received) </li></ul></ul>
  42. 42. Ping – step by step <ul><li>Ping (loopback, is TCP/IP OK?) </li></ul><ul><li>Ping own IP address (are NIC hardware and software all right? Is IP address bound?) </li></ul><ul><li>Ping local hosts (checks own configuration and that of others) </li></ul><ul><li>Ping gateway </li></ul><ul><li>Ping other intermediate routers </li></ul><ul><li>Ping hosts on remote networks </li></ul>
  43. 43. Network baseline <ul><li>Measure and record performance </li></ul><ul><ul><li>At different times </li></ul></ul><ul><ul><li>Under different conditions </li></ul></ul><ul><ul><li>Repeatedly over a period of time </li></ul></ul><ul><li>Build up a record of network performance </li></ul><ul><li>Useful in troubleshooting and optimising the network </li></ul><ul><li>Helps predict future problems </li></ul><ul><li>Helps planning for change </li></ul>
  44. 44. Find out about nodes <ul><li>Ping – used from workstation, router or switch – shows if destination can be reached </li></ul><ul><li>Traceroute – shows hops along the path </li></ul><ul><li>Arp -a on workstation – shows list of MAC and IP addresses </li></ul><ul><li>show mac-address-table on switch – shows list of MAC addresses and switch ports </li></ul>
  45. 45. Summary <ul><li>Hierarchical Design model addresses performance, scalability, maintainability & manageability issues. </li></ul><ul><li>Traffic Analysis is used to monitor network performance. </li></ul><ul><li>Hierarchical Design Model is composed of 3 layers: </li></ul><ul><ul><li>Access </li></ul></ul><ul><ul><li>Distribution </li></ul></ul><ul><ul><li>Core </li></ul></ul><ul><li>Switches selected for each layer must meet the needs of each hierarchical layer as well as the needs of the business. </li></ul>
  46. 46. Labs & Activities * If no previous Packet Tracer experience, else strongly recommended Mandatory 11..2.3 Lab Mandatory* 11.1.6 Lab Review carefully 11.2.2 Lab Mandatory 11.2.1 Lab Mandatory 11.1.7 Lab Detail Type