mod11
DESCRIPTION
TRANSCRIPT
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 1
Configuring and testing
CCNA Exploration Semester 1 – Chapter 11
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 2
Topics
The Internetwork Operating System (IOS).
Devices that have the IOS embedded.
IOS commands available to a device.
IOS modes of operation.
Basic IOS commands.
Basic show commands.
Configuration files
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Internetwork Operating System
Most Cisco devices use the Cisco IOS.
Details vary with the device and feature set.
Normal access through a command line.
Stored in flash memory and can be upgraded.
Usually copied into RAM when the device is powered on, and run from RAM.
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Access to the interface
Console port via serial connectionInitial configuration
Disaster recovery
When network access has failed
Password recovery
As well as general management
Console access does not require a password. Configure a password. Lock the door.
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Telnet, SSH, Aux
Later management can be via Telnet
There must be an IP address on the port
A password must be configured
Secure shell gives better security
AUX port can be used locally or via modem but by default does not show error messages
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Configuration files
Hold the commands that have been configured on the router to customise it.
Running configuration in RAM holds commands that are in current use
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.
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Router storage areas
ROM
Permanent
Holds POST, boot instructions, basic IOS
Flash
Keeps contents
Holds IOS image
NVRAM
Keeps contents
Holds startup configuration file
RAM
Volatile
Holds runnning config, tables, queues etc
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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 EndVarious commands
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Router prompts
User EXEC mode
Privileged EXEC mode
Global Configuration mode
Specific Configuration modes
Router>
Router#
Router(config)#
Router(config-if)#and others
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EXEC modes
You log in to User EXEC modeRouter>
You can give basic monitoring commands but cannot change the configuration
Enter enable to go to Privileged EXEC modeRouter#
Password may be used for security
You can give more commands and can go to configuration modes
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Configuration modes
Start in privileged EXEC mode and enter the configure terminal (config t) commandRouter# config tRouter(config)#
The prompt changes
This is global configuration mode
Additional commands take you to interface configuration, router configuration etc.
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Leaving configuration modes
From interface configuration mode there are several ways of getting to privileged EXEC
Router(config-if)# exit Router(config)# exit Router#
Router(config-if)# endRouter#
Router(config-if)# Ctrl+zRouter#
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Command Structure
Followed by <Enter>
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? To get help
? Gives a list of commands available from the current prompt.
Command followed by space then ? Gives a list of keywords or arguments that can be used.
Start of command followed by ? with no space shows how the word can be continued.
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Shortened commands
Router#show running-config
Router#show run
Router#sh ru
It needs enough letters of each word to be unambiguous. (Tab key shows whole word)
Router#s ru
% Ambiguous command: ‘s’
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Other error messages
Switch#clock set
% Incomplete command
Switch#clock set 19:50:00 25 6
% Invalid input detected at ‘^’ marker
Router#show runming-config
% Invalid input detected at ‘^’ marker
^
^
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Keyboard shortcuts
Tab completes a partial command
Backspace erases to left of cursor
Ctrl+D erases at cursor (Delete does not)
Ctrl+Z returns from any config mode to privileged exec mode
Ctrl+C leave Setup mode
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Show commands
Show ? To get a list
Many different show commands to give information about every aspect of the router and its operation
We use some of the most common.
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General show commands
Show running-config shows the configuration file from RAM
Show startup-config shows the saved configuration file from NVRAM
Show version gives information about the IOS and the router itself. It shows the configuration register, which controls how the router starts up.
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Show interfaces
Gives statistics for all interfaces
In particular, says if the interface is up and if the protocol is up – important in troubleshooting.
Show interfaces serial 0/0 to show one selected interface
You can shorten to show int s 0/0
Show ip interfaces gives IP statistics
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Save configuration
Router#copy running-config startup-config
Router#copy run start (shortened)
Router#wr (Old fashioned, short for write, but it works and is safe.)
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.
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Hostname
Router>enable
Router#config t
Router(config)#hostname Paris
Paris(config)#
Configure a suitable hostname so that you know which router you are managing and so that you can identify it in network documentation.
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Console password
Paris(config)#line con 0
Paris(config-line)#password cisco
Paris(config-line)#login
Paris(config-line)#exit
Restricts access via the console
Use cisco as the password in labs.
Use a proper strong password on production networks
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Vty password for Telnet
Paris(config)#line vty 0 4
Paris(config-line)#password cisco
Paris(config-line)#login
Paris(config-line)#exit
Allows and restricts access via 5 vty lines
Use cisco as the password in labs.
Use a proper strong, different password on production networks
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Enable and enable secret
Paris(config)#enable secret class
The password class is needed when you type enable to enter privileged exec mode
This password is encrypted
Paris(config)#enable password cisco
Not encrypted, used on older routers
If you configure both, then only the enable secret is used.
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Message of the day
Paris(config)#banner motd # No unauthorised access #
# is a delimiter to show where the message starts and ends.
Any character can be used as long as it does not appear in the message.
The message should make it clear that unauthorised access is forbidden.
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Reload
Shuts down the router and then starts it again.
If the configuration has changed then you are prompted to save it.
The running configuration in RAM is lost.
The startup configuration from NVRAM is (usually) loaded into RAM on startup.
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Back up to TFTP server
Start TFTP server software on host
Paris#copy running-config tftp
Remote host []? 172.16.1.1
Name of configuration file to write [Paris-config]? Paris12Oct07
Write file Paris12Oct07 to 172.16.1.1? [confirm] y
Writing Paris12Oct07 ! ! ! ! ! ! [OK]
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Back up as text file
Start text capture
Name file
show run
Stop text capture
Open saved file and
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TeraTerm text file
TeraTerm is an open source Telnet client.
It can also act as a SSH client
It can capture text and save it as a file.
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Erase startup configuration
Paris#erase NVRAM:startup-config
Paris#erase startup-config
Paris#erase start
If you reload, then the router starts up with the default configuration. No passwords, no IP addresses etc.
Caution if you get this command wrong then you could erase something else, e.g. IOS
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Restore file from TFTP server
Router#copy tftp running-config
You will be prompted for IP address and file name.
Configuration is copied into RAM and takes effect at once.
Save to NVRAM.
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Restore text file
Go to global configuration mode
Hyperterminal Transfer menu
Send text file…
Or
Copy text from text file
“Paste to host” into Hyperterminal session
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Configure a router interface
Paris(config)#interface FastEthernet 0/0
Paris(config-if)#ip address 172.16.1.1 255.255.0.0
Paris(config-if)#no shutdown
Paris(config-if)#exit
Interface names vary, depending on whether the router is modular and on the bandwidth.
E.g. interface Ethernet 0 on an older router
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Configure a router interface
Paris(config)#interface serial 0/0
Paris(config-if)#ip address 192.168.4.1 255.255.255.0
(Paris(config-if)#clock rate 64000)
Paris(config-if)#no shutdown
Paris(config-if)#exit DCE only
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Description
Paris(config)#interface fa0/0
Paris(config-if)#description Connects to Paris central switch
Can include circuit and contact information
Not needed for the operation of the router
Valuable for documentation as it is included in the configuration listing
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Switch interfaces
Switch physical interfaces do not have IP addresses
They are active by default and do not need the no shutdown command.
It can be useful to give them a description.
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Switch IP address
The switch IP address goes on a virtual interface, not a real one, normally VLAN1.
SwA(config)#interface VLAN1
SwA(config-if)#ip address 172.16.255.1 255.255.0.0
SwA(config-if)#no shutdown
SwA(config-if)#exit
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Switch default gateway
SwA(config)#ip default gateway 172.16.255.254
Just like a workstation, a switch needs a default gateway if it exchanges messages with devices on a different network.
The default gateway is the address of the local router.
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Interface – show commands
show interfaces states whether up or down, gives some protocol information and statistics about interface use.
show ip interface gives IP addresses and much more.
show ip interface brief gives summary of IP addresses and whether up/down. Very useful command.
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Up or down
Interface status: Layer 1Up
Down
Administratively down (no shutdown to bring up)
Protocol: Layer 2Up
Down (no keepalive signal received)
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Ping – step by step
Ping 127.0.0.1 (loopback, is TCP/IP OK?)
Ping own IP address (are NIC hardware and software all right? Is IP address bound?)
Ping local hosts (checks own configuration and that of others)
Ping gateway
Ping other intermediate routers
Ping hosts on remote networks
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Network baseline
Measure and record performanceAt different times
Under different conditions
Repeatedly over a period of time
Build up a record of network performance
Useful in troubleshooting and optimising the network
Helps predict future problems
Helps planning for change
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Find out about nodes
Ping – used from workstation, router or switch – shows if destination can be reached
Traceroute – shows hops along the path
Arp -a on workstation – shows list of MAC and IP addresses
show mac-address-table on switch – shows list of MAC addresses and switch ports
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Summary Hierarchical Design model addresses performance,
scalability, maintainability & manageability issues.
Traffic Analysis is used to monitor network performance.
Hierarchical Design Model is composed of 3 layers:Access
Distribution
Core
Switches selected for each layer must meet the needs of each hierarchical layer as well as the needs of the business.
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Labs & Activities
Type Detail
Lab 11.1.6 Mandatory*
Lab 11.1.7 Mandatory
Lab 11.2.1 Mandatory
Lab 11.2.2 Review carefully
Lab 11..2.3 Mandatory
* If no previous Packet Tracer experience, else strongly recommended
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