Pertemuan 5
Configuring a Router
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Discussion Topics
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CLI command modes
Configuring a router name
Configuring router passwords
Examining the show commands
Configuring a serial interface
Making configuration changes
Configuring an Ethernet interface
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Command-Line Interface
Command Modes
Configuring a Router Name
Configuring a router name
Mistake…
Should be…
Router#config t
Router(config)#hostname Tokyo
Tokyo(config)#
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Configuring Router Passwords
service password-encryption
command
WARNING
• service password-encryption uses a Cisco Level 7
encryption which is very easy to decrypt.
• For the GetPass! software www.boson.com
• However, the enable secret <password> uses a stronger
encryption method and cannot be easily hacked.
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Examining the show commands
• 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
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Examining the show commands
• 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
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Examining the show Commands
• Many show commands can be used to
examine the contents of files in the router
and for troubleshooting.
• In both privileged EXEC and user EXEC
modes, the command show ? provides a
list of available show commands.
Interface Configuration Commands
Configuring an Ethernet
Interface
show ip interface command
Router# show ip interface brief
Interface
Ethernet0
Serial0
IP-Address
131.108.1.11
198.135.2.49
OK?
YES
YES
Method
manual
manual
Status
up
administratively down
Protocol
up
down
What is wrong here? The administrator has either done a
“shutdown” on the interface or has forgotten to do a “no shutdown”.
• A serial interface will not show “up” and “up” unless both ends are
properly configured (mostly) and a the no shutdown command is used.
• If one router’s configuration looks okay, check the other router’s
configuration.
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Configuring a serial interface
Lab
Real world
• 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
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Configuring a serial interface
RouterA DTE
cable
RouterB DCE
cable
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
RouterB(config-if)#clock rate 64000
Rick Graziani
RouterB(config-if)#
graziani@cabrillo.edu
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Configuring a serial interface
DTE Cable
DCE Cable
How can you tell which end is the DTE and which end is the DCE?
 Look at the label on the cable.
 Look at the connecter between the two cables - The DTE cable will
always be male and the DCE cable will always be female.
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Configuring a serial interface
RouterA DTE
cable
RouterB DCE
cable
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
This is one of few commands where there must be a space between the interface type and the port.
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
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Configuring a serial interface
This end up!
(The wider end is up.)
• Please be very careful when connecting the male and female
V.35 cables together AND when connecting the serial cable to
the router!
• They only connect ONE WAY!
• Be sure the two ends match!
• Don’t force it!
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Executing adds, moves, and
changes
running-config
IOS (running)
startup-config
IOS
Bootup program
ios (partial)
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