Basic IOS
Accessing the Switch and Router
 Directly using the console port
o No configuration needed on the router
 Telnet – over the network
o Network connection
o Network configuration on both ends (IP address, subnet mask, etc.)
o Telnet password configured on router
 Modem – We won’t do this!
Accessing the router and switch directly
 The console port on the router allows you to connect a “dumb” terminal or a computer
with terminal emulator software directly.
 No IP addressing or other configurations needed on the router.
 Used for:
o Configuring a device that has never been configured.
o Configuring a device directly, because you are physically located where the
device is.
o Troubleshooting a device that you can no longer access remotely.
o Performing password recovery.
Terminal Emulators
 HyperTerminal: Comes with Windows
 Teraterm: Free download (recommended)
 Settings:
o 9600 Baud
o 8 Data Bits
o 1 Stop Bit
o No Parity
Power-up the router (and switch) – No configuration
If the routers do not have a saved configuration, after several lines of information on the screen
you should eventually see:
Would you like to enter the initial configuration dialog? [yes/no]: n
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Always answer “n” fo no.
We will never be using setup mode.
If you accidentally press “y” and enter Setup Mode, press and hold down the control key
and press C (CTRL-C).
Wait a few seconds, and then press Enter.
On some routers you may see the following message.
Would you like to terminate autoinstall? [yes/no]: y
<There will be several lines of output>
Router>
1
Power-up the router (and switch) – Has Configuration
The router has a pre-existing configuration.
If after you power-up the router, instead of getting the previous message, you get:
Router>
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Someone has saved a configuration on the router (startup-config).
Because it is always best to begin our labs without a previous router configuration, you
will need to erase the startup-config and reboot the router.
Router> enable

If you are prompted for a password type: class or if that does not work, type cisco
Router# erase startup-config

Turn off the router and then turn it back on.
User Mode and Privilege Mode, Getting Help, and Abbreviated Commands
User Mode (Router and Switch)
Router>
Switch>
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User mode will allow you to view the state of the router, but will not allow you to modify its
configuration.
Don’t confuse “user” mode with users of the network.
This is only for network techs, operators, engineers, etc.
Privilege Mode (Router and Switch)
Router> enable
Router#

<user mode>
<privilege mode>
Allows the administrator to modify the router configuration
Router# disable
<privilege mode>
Router> enable
Router#
<user mode>
<privilege mode>
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Getting Help (Router and Switch)
Router> ?
Exec commands:
access-enable
access-profile
clear
<text omitted>
ping
ppp
--More-
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Create a temporary Access-List entry
Apply user-profile to interface
Reset functions
Send echo messages
Start IETF Point-to-Point Protocol (PPP)
Press the Space Bar to scroll a “screen’s worth” of more commands.
Press the Enter or Return key to scroll down just one line of the list.
Press any other key to halt the list output.
Router> show ?
alps
backup
c2600
call
cca
ccm-manager
cdapi
cef
class-map
clock
<text omitted>
--More—
Router> show
Alps information
Backup status
Show c2600 information
Show call
CCA information
Call Manager Application information
CDAPI information
Cisco Express Forwarding
Show QoS Class Map
Display the system clock
Router> show interfaces ?
Async
Async interface
BRI
ISDN Basic Rate Interface
BVI
Bridge-Group Virtual Interface
<text omitted>
Router> show interfaces
Abbreviated commands (Router and Switch)
Router# sh inter
Same as
Router# show interfaces
3
Global Configuration Mode and Passwords
Using exit, end and Control-Z
Router>ena
Router#configure terminal <Must be in privileged mode>
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#?
Configure commands:
access-list
Add an access list entry
<text omitted>
Router(config)#exit
00:03:20: %SYS-5-CONFIG_I: Configured from console by con
Router#config t
Enter configuration commands, one per line.
End with CNTL/Z.
Router(config)#exit
00:03:34: %SYS-5-CONFIG_I: Configured from console by console
Router#
Hostname
Router#config t
Router(config)#hostname R1
R1(config)#
Passwords
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There are only two passwords we will use in our classes, they are cisco and class. (both
lowercase).
Of course this is something you would not do in a production network, but so we do not
have to do password recovery on equipment and to make it easier for everyone, we will
use only these two passwords.
Console = cisco
VTY = cisco
Priviledge = class
Console password = cisco

The console password requires someone to enter a password before accessing the
router using the console port.
Router#conf t
R1(config)#line console 0
R1(config-line)#password cisco
R1(config-line)#login
R1(config-line)#exit
R1(config)#
4
VTY password = cisco

The vty password requires someone to enter a password before accessing the router
remotely using telnet.
R1(config)#line vty 0 4
R1(config-line)#password cisco
R1(config-line)#login
R1(config-line)#exit
R1(config)#
Privilege password = class

The privilege mode password requires someone to enter a password when entering
privilege mode with the enable command.
R1(config)#enable secret class
R1(config)#end
R1#
Test it:
R1#disable
R1>enable
Password:class
R1#
Viewing, Saving and Erasing the Configurations
running-config
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The running-config file is the configuration in RAM memory.
All changes are made to the running-config file.
This is the configuration that the router is currently using.
The running-config is lost when the router loses power or reloads.
Privilege mode command.
Router#show running-config
Current configuration : 542 bytes
!
version 12.2
!
interface FastEthernet0/0
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/0
no ip address
shutdown
!
line con 0
line aux 0
5
line vty 0 4
!
end
Router#
startup-config
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The startup-config file is the saved configuration in NVRAM.
If there is a startup-config file in NVRAM when the router boots up, this file will be copied
into running-config.
The running-config is what the router will use.
Privilege mode command.
Router#show startup-config
startup-config is not present
Router#
Copy running-config to startup-config

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The running-config should be periodically saved to startup-config when you are satisfied
with your changes and you do not want to lose them. (Lab)
Production network, startup-config should always match running-config in case of power
failure, etc.
Privilege mode command.
Router#copy running-config startup-config
Destination filename [startup-config]? <Press Enter>
Building configuration...
[OK]
Router#show startup-config
Current configuration : 542 bytes
!
version 12.2
!
interface FastEthernet0/0
<text omitted>
Erase startup-config

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When you are done with the routers in the lab, please be sure to erase the startup-config.
If you are starting a lab, and you do not get the message:
Would you like to enter the initial configuration dialog?
[yes/no]:
You will need to erase the startup-config and reboot.
Privilege mode command.
Router#erase startup-config
Erasing the nvram filesystem will remove all files! Continue? [confirm]
<Press Enter>
[OK]
Erase of nvram: complete
Router#
6
copy running-config startup-config
Router# copy running-config startup-config
Or
Router# copy running startup
OR
Router# copy run start
OR
Any usage of the command or parameters, so that they are still uniquely recognizable.
reload
Router#erase startup-config
Router#reload
Managing Console Input
Router(config)#line console 0
Router(config-line)#logging synchronous
Router(config-line)#exec-timeout 0 0
Router(config-line)#exit
Router(config)#no ip domain-lookup
The Router Interfaces
Interfaces

A quick look at the interfaces.
Router#show ip interface brief
Interface
IP-Address
FastEthernet0/0
unassigned
Serial0/0
unassigned
BRI0/0
unassigned
BRI0/0:1
unassigned
BRI0/0:2
unassigned
Serial0/1
unassigned
Router#
OK?
YES
YES
YES
YES
YES
YES
Method
unset
unset
unset
unset
unset
unset
Status
administratively
administratively
administratively
administratively
administratively
administratively
Protocol
down down
down down
down down
down down
down down
down down
Configuring an Ethernet interface
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Your interfaces may differ!
Adding an IP address and subnet mask
no shutdown – turns on the interface.
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#inter fastethernet 0/0
Router(config-if)#ip add 172.30.1.1 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#end
Router#
7
Configuring a serial interface
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Your interfaces may differ!
Adding an IP address and subnet mask
no shutdown – turns on the interface
R1(config)#inter serial 0/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no shutdown
R1(config-if)#exit
Examining the show commands
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show interfaces – Displays all the statistics for all the interfaces on the router. To view
the statistics for a specific interface, enter the show interfaces command followed by the
specific interface and port number.
show controllers serial – Displays information-specific to the interface hardware
show clock – Shows the time set in the router
show hosts – Displays a cached list of host names and addresses
show users – Displays all users who are connected to the router
show history – Displays a history of commands that have been entered
show flash – Displays information about flash memory and what IOS files are stored
there
show version – Displays information about the router and the IOS that is running in RAM
show ARP – Displays the ARP table of the router
show protocol – Displays the global and interface specific status of any configured
Layer 3 protocols
show startup-configuration – Displays the saved configuration located in NVRAM
show running-configuration – Displays the configuration currently running in RAM
show interfaces <interface> command
Router>show interface ethernet 0
Ethernet0 is administratively down, line protocol is down , using hub 0
Hardware is Lance, address is 0010.7b3a.cf84 (bia 0010.7b3a.cf84)
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load
1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 01:05:35, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 input packets with dribble condition detected
63 packets output, 11676 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
Router>
8
Where is the MAC Address?
Router>show interface serial 0
Serial0 is administratively down, line protocol is down
Hardware is HD64570
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load
1/255
Encapsulation HDLC, loopback not set, keepalive set (10 sec)
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
28 packets output, 9576 bytes, 0 underruns
0 output errors, 0 collisions, 17 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=down DSR=down DTR=down RTS=down CTS=down
Router>
Configuring a serial interface
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On serial links that are directly interconnected, as in a lab environment, one side must be
considered a DCE and provide a clocking signal.
The clock is enabled and speed is specified with the clock rate command.
Router(config)#interface serial 0/0
Router(config-if)#clock rate 56000
Router(config-if)#no shutdown
Configuring a serial interface
RouterB(config)#inter serial 1
RouterB(config-if)#clock rate ?
Speed (bits per second)
1200
2400
4800
9600
19200
38400
56000
64000
<text omitted>
2000000
4000000
<300-4000000>
Choose clockrate from list above
9
RouterB(config-if)#clock rate 64000
RouterB(config-if)#
Configuring a serial interface
RouterA#show controllers serial 0
HD unit 0, idb = 0xECA4C, driver structure at 0xF1EC8
buffer size 1524 HD unit 0, V.35 DTE cable
cpb = 0x62, eda = 0x403C, cda = 0x4050
RX ring with 16 entries at 0x624000
00 bd_ptr=0x4000 pak=0x0F5704 ds=0x62FFB8 status=80 pak_size=22
RouterB#show controllers serial 0
buffer size 1524 HD unit 0, V.35 DCE cable, clockrate 64000
cpb = 0x62, eda = 0x408C, cda = 0x40A0
RX ring with 16 entries at 0x624000
00 bd_ptr=0x4000 pak=0x0F2F04 ds=0x627908 status=80 pak_size=22
Switch Configuration
Physical startup of the Catalyst switch
Show running-config
ALSwitch#show running-config
Building configuration...
Current configuration : 1300 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname ALSwitch
!
!
ip subnet-zero
!
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface FastEthernet0/1
10
Set Port Speed and Duplex Settings
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The Fast Ethernet switch ports default to:
o auto-speed
o auto-duplex.
This allows the interfaces to negotiate these settings.
When a network administrator needs to ensure an interface has particular speed and
duplex values, the values can be set manually.
HTTP Service and Port


A web browser can access this service using the IP address and port 80, the default port
for http.
The HTTP service can be turned on or off, and the port address for the service can be
chosen.
Managing the MAC address table
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Switches learn the MAC addresses of PCs or workstations that are connected to their
switch ports by examining the source address of frames that are received on that port.
Machines may have been removed from a port, turned off, or moved to another port on
the same switch or a different switch.
This could cause confusion in frame forwarding.
The MAC address entry is automatically discarded or aged out after 300 seconds.
Switch#show mac-address-table
Managing the MAC address table

Rather than wait for a dynamic entry to age out, the administrator has the option to use
the privileged EXEC command clear mac-address-table.
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