The following commands are executed by pressing the appropriate key:
- Question Mark: Gets help.
- Use at any prompt to see what commands can be executed there.
- Type in the beginning of a command, followed directly by a question mark (no space in between), to see the commands starting with those characters.
- Type in a command, then a space, then a question mark, to see options.
- Q: When in user or privileged EXEC mode, logs you out of the router. When at the "---More---" prompt, returns you to the EXEC prompt.
- Tab: Completes a partial command name entry.
- Backspace: Erases the character to the left of the cursor.
- Return: When at the "---More---" prompt, displays the next line.
- Space Bar: When at the "---More---" prompt, displays the next screen.
- Left Arrow: Moves the cursor one character to the left (same as Ctrl-B).
- Right Arrow: Moves the cursor one character to the right (same as Ctrl-F).
- Up Arrow: Recalls commands in the history buffer, beginning with the most recent command (same as Ctrl-P).
- Down Arrow: Recalls more recent commands in the history buffer (same as Ctrl-N).
The following commands are executed by pressing the keys simultaneously:
- Ctrl-A: Moves the cursor to the beginning of the line.
- Ctrl-B: Moves the cursor back one character (same as Left Arrow).
- Ctrl-C: When in any config mode, ends the config mode and returns you to privileged EXEC mode.
- Ctrl-D: Deletes the character at the cursor.
- Ctrl-E: Moves the cursor to the end of the command line.
- Ctrl-F: Moves the cursor forward one character (same as Right Arrow).
- Ctrl-I: Redisplays the system prompt and command line (same as Ctrl-L and Ctrl-R).
- Ctrl-K: Deletes all characters from the cursor to the end of the command line.
- Ctrl-L: Redisplays the system prompt and command line (same as Ctrl-I and Ctrl-R).
- Ctrl-N: Recalls more recent commands in the history buffer (same as Down Arrow).
- Ctrl-P: Recalls commands in the history buffer, beginning with the most recent command (same as Up Arrow).
- Ctrl-R: Redisplays the system prompt and command line (same as Ctrl-I and Ctrl-L).
- Ctrl-T: Transposes the character to the left of the cursor with the character located at the cursor.
- Ctrl-U: Deletes all characters from the cursor back to the beginning of the command line (same as Ctrl-X).
- Ctrl-V: Inserts a code to indicate to the system that the keystroke immediately following should be treated as a command entry, not as an editing key (same as Esc Q).
- Ctrl-W: Deletes the word to the left of the cursor.
- Ctrl-X: Deletes all characters from the cursor back to the beginning of the command line (same as Ctrl-U).
- Ctrl-Y: Recalls the most recent entry in the delete buffer. The delete buffer contains the last ten items you have deleted or cut. Ctrl-Y can be used in conjunction with Esc Y.
- Ctrl-Z: When in a config mode, ends the config mode and returns you to privileged EXEC mode. When in user or privileged EXEC mode, logs you out of the router.
- Ctrl-Shift-6: All-purpose break sequence. Use to abort DNS lookups, traces, pings, etc.
- Ctrl-Shift-6, followed by X: Suspends (but doesn't terminate) a telnet session. To see the open sessions, use "show sessions". To return to a suspended session, enter that session's number followed by the * Return key. To return to the most recently suspended session, hit the Return key at the EXEC mode prompt.
The following commands are executed by pressing and releasing the escape key, and then pressing the appropriate letter:#
- Esc B: Moves the cursor back one word.
- Esc C: Capitalizes the word from the cursor to the end of the word.
- Esc D: Deletes from the cursor to the end of the word.
- Esc F: Moves the cursor forward one word.
- Esc L: Changes the word to lowercase from the cursor to the end of the word.
- Esc Q: Inserts a code to indicate to the system that the keystroke immediately following should be treated as a command entry, not as an editing key (same as Ctrl-V).
- Esc U: Capitalizes from the cursor to the end of the word.
- Esc Y: Recalls the next buffer entry. The buffer contains the last ten items you have deleted. Press "Ctrl-Y" first to recall the most recent entry. Then do "Esc Y" up to nine times to recall the remaining entries in the buffer. If you bypass an entry, continue to press "Esc Y" to cycle back to it.
You'll also find the following commands to be useful (when specifying options, don't include the brackets):
- conf t: When in privileged EXEC mode, puts you into global config mode.
- copy run start: Saves the running config to NVRAM. This is an overwrite.
- copy start run: Merges the startup config into the running config. This is NOT an overwrite.
- debug option: Starts the specified debugging. Use "debug ?" to see the choices.
- en (enable): When in user EXEC mode, gets you into privileged EXEC mode.
- end: When in a config mode, takes you back to privileged EXEC mode.
- ex (exit): When in user or privileged EXEC mode, logs you out of the router. When in global config mode, takes you to privileged EXEC mode. When in a specific config mode, takes you back to global config mode.
- int type number: When in any config mode, takes you to interface config mode for the specified interface.
- logg sync (logging synchronous): When in line config mode, turns on automatic redisplay of command lines interrupted by console messages.
- no logging console: When in global config mode, shuts off informational messages ("logging console" turns them back on).
- no ip domain-lookup: When in global config mode, shuts off DNS name resolution ("ip domain-lookup" turns it back on).
- router protocol AS-number: When in global config mode, takes you to router config mode for the specified IP routing protocol.
- term mon (terminal monitor): When in line config mode, sends debugging messages to the chosen terminal line.
- un all (undebug all): When in privileged EXEC mode, shuts off all debugging.
Show Commands#
Commonly used "show" commands (when specifying options, don't include the brackets):- sh config: The obsolete, pre-10.3 version of "sh start".
- sh cont type number: Layer-1 info for specified interface, including cable type, DTE/DCE, etc. Example: "sh cont e 3" (NOT "sh cont e3").
- sh int type number: Layer-2 info for specified interfaces. Example: "sh int e0".
- sh protocol int type number: Layer-3 info for the specified protocol and interface. Example: "sh ip int s2".
- sh proto: Active Layer 3 protocols.
- sh ip proto: Active IP routing protocols.
- sh protocol route: Routing table for the specified protocol. Example: "sh ip route".
- sh run (show running-config): Shows the running config. Obsoletes "write terminal".
- sh start (show startup-config): Shows the startup config. Obsoletes "show config".
- wr term: The obsolete, pre-10.3 version of "sh run".
Copy TFTP commands (used to backup and restore configs and IOS):#
- copy flash tftp: Copies a file from flash to a TFTP server.
- copy run tftp: Copies the running config to a TFTP server.
- copy start tftp: Copies the startup config to a TFTP server.
- copy tftp flash: Copies a file from a TFTP server to flash.
- copy tftp run: Merges a file on the TFTP server into the running config.
- copy tftp start: Replaces the startup config with a file from a TFTP server.
Hints for "copy" commands which involve a TFTP server ...#
Make sure that the TFTP server software is configured and running. Make sure that the router can see the TFTP server (PING it). Execute the appropriate "copy" command. Make sure that you READ THE QUESTIONS before you answer them!Useful terms:#
- Flash: Special type of RAM that does not lose its contents when power is removed. Used to store IOS.
- IOS (Internetwork Operating System): Cisco's operating system. Stored in flash.
- NVRAM (Non-Volatile RAM): RAM with a battery attached, used to store the startup config.
- POST (Power-On Self-Test): Diagnostics performed at boot-up, tests the hardware.
- RAM (Random-Access Memory): Stores frequently-changing data, such as ARP caches, routing tables, packets awaiting forwarding, etc.
- ROM (Read-Only Memory): Chipset on system board where POST and boot loader (and, on some routers, an IOS subset) are stored.
- running config (also known as "current" or "active" config): How the router is currently configured. Stored in RAM.
- startup config (also known as "backup" config): How the router will be configured at the next restart. Stored in NVRAM.
Remember ...#
- Show commands don't work from ANY config mode.
- Config commands don't work from user or privileged EXEC mode.
- Hot keys and command keywords are not case-sensitive, BUT PASSWORDS ARE!
- Some (not all!) of these commands work on some (not all!) of the switches.
Basic Router Commands
To get into Privilege Mode from User
mode - enable
To exit out of Privilege mode disable
To exit the router - Exit or logoff
Previous Command - Up arrow or Ctrl-P
Next Command - Down arrow or Ctrl-N
Move forward one character - Right arrow or Ctrl-F
Move back one character - Left arrow or Ctrl-B
Break Key or Cancel - <ctrl>“c”
Auto Complete the command - <tab>
Setting Passwords
Set Password for Console Port line console 0
login
password password
Set Password for Telnet
line vty 0 4
login
password password
Set Password for Privilege (Enabled) mode
enable password password
Set Encrypted password for Privilege mode
enable password password
Router Configuration Commands
To go from Privilege mode to Global
Configuration mode
configure terminal
To copy the running-configuration to the
start-up configuration
copy run start
To copy the startup-config to the runningconfig
copy start run
To copy the startup-config to a TFTP
server
copy start tftp
To copy the running-config to a TFTP
server
copy run tftp
Save a backup of the IOS to a TFTP server
copy flash tftp
Upgrade the IOS from a TFTP server
copy tftp flash
Tell the router which IOS in flash to boot
from
boot system flash {filename}
Tell the Router which IOS to request from
a TFTP server (usually a fallback option)
boot system tftp {filename}
Viewing the Router’s Information
IOS Version info
show version
Current config stored in RAM
show running-config
Configuration stored in NVRAM
show startup-config
To see IOS info stored in flash
show flash
To see information on the interfaces
show interfaces
To see a summary of the interfaces
show ip int brief
To see processor utilization show processes cpu
Configuring an Interface
To access an interface “From Global config”
interface {type} {number}
example : interface Ethernet 0
To set Clock rate on a serial interface
Clock rate {kbps}
Example : clock rate 64000
Enable the interface
no shutdown
Disable the interface
shutdown
Assign an IP address to an Interface ip address {Ip address} {subnet mask}
Example: ip address 10.1.1.1 255.255.255.0
Configuring TCP/IP
To enable IP routing on a Router “From Global config”
ip routing
To disable IP routing on a Router
“From Global config”
no ip routing
Displays values about routing timers,
networks, and routing information.
show ip protocols
Displays contents of the routing table.
show ip route
Assign an [IP Address] to an Interface ip address {Ip address} {subnet mask}
Example: ip address 10.1.1.1 255.255.255.0
Manually setups up a host table mapping a
hostname to an ip address.
ip host name “ ip” “addresss”
Displays the host table show hosts
Configure RIP router rip
network “network address”
Configure IGRP Router rip
Network “network address”
Displays RIP updates [debug] ip rip
Displays IGRP transactions debug ip igrp transactions
Displays IGRP summary transactions Debug ip igrp events
Displays status and global parameters
associated with an interface
show ip interfaces
Allows remote management of a device telnet “ip address of host”
Uses ICMP to verify hardware connection
and logical address of the network layer
ping “network address”
To setup a static route ip route “network” “mask” “next hop address”
IPX configuration
Enable IPX on a router ipx routing
To enable load balancing ipx maximum-paths “number”
To assign a IPX network address to an
interface
ipx network “network number”
To set the encapsulation type on an
interface
encap novell-ether
encap sap
encap arpa
encap snap
To view the IPX routing table show ipx route
To view an IPX address on an interface show ipx interface
To view the sap table show ipx servers
To view IPX traffic statistics show ipx traffic
To view the IPX rip updates debug ipx routing activity
To view the SAP packets coming and
going
debug ipx sap
Cisco Discovery Protocol
See info on directly connected neighbors
Add “detail” to the end for more info
show cdp neighbors
To see what interfaces are runnning CDP
show cdp interface
To specify and particular neighbor and see
CDP information
show cdp entry “hostname”
To turn off CDP for the entire router no cdp run
To turn off CDP for an interface No cdp enable
To change how often the router sends CDP
updates
cdp timer “seconds”
To change how long the router will wait
before it’s removes a CDP neighber from
it’s table
cdp holdtime “seconds”
Access-Lists
IP Standard Access Lists 1-99
Set parameters for this access list
test statement
access-list access-list-number,
permit |deny, source, [source-mask]
Enable an interface to become part
of a group that uses the specified
access list.
protocol access-group access-listnumber,
in | out
IP Extended Access Lists 100-199
Set parameters for this access list
entry
access-list Access-list-number,
permit |deny, protocol, source,
source-mask,
destination, destination-mask,
[operator
operand], [established]
Enable an interface to become part
of a group that uses the specified
access list.
protocol access-group accesslist-
number, in | out
Assigns an alpha-numeric name
string to an access list
ip access-list standard |
extended name
Activates the access list on an
interface
ip access-group name | 1-199,
in | out
Can be used to verify whether
access lists are set
show ip interfaces
Displays the contents of all access
lists
show access-lists
IPX Standard Access Lists 800-899
Set parameters for this access list
entry
access-list Access-list-number,
permit | deny, source-network
[.source-node],
[source-node-mask], [destinationnetwork],
[.destination-node] [destinationnode-
mask]
Enable an interface to become part
of a group that uses the specified
access list.
ipx access-group access-listnumber,
in | out
IPX Extended Access Lists 900-999
Set parameters for this access list
entry
access-list Access-list-number,
permit |
deny, protocol, source-network
[[[.source-node]source-node-mask] |
[.source-node
source-network-mask.source-nodemask]],
[source-socket], [destinationnetwork],[[[.
destination-node] destination-node-
mask] | [destination-node
destination-network-
mask.destination-node-mask]],
[destination-socket], [log]
Enable an interface to become part
of a group that uses the specified
access list.
ipx access-group access-listnumber,
in | out
IPX SAP Filter Access Lists 1000-
1099
Creates an entry in a SAP filter
list
access-list Access-list-number,
permit |
deny, network [.node], [networkmask
node-mask], [service-type [servername]]
Activates the output SAP filter on
the interface
ipx output-sap-filter accesslist-
number
Activates the input SAP filter on
the interface
ipx input-sap-filter accesslist-
number
Displays information about the
config of the interface including
SAP filter numbers.
show ipx interface
WAN configuration
PPP Authentication
On each router defines the username
and password to
expect from the remote router
username name password secret
Configure the interface for ppp
encapsulation
encapsulation ppp
Configure ppp authentication type PPP authentication chap | chap pap
|pap chap | pap
Enables PAP on an interface
(disabled by default)
ppp pap sent-username
username password password
To use the same host name on
multiple routers
ppp chap hostname hostname
Use to authenticate to an unknown
host. This password is
not used when the router
authenticates a remote device.
ppp chap password secret
Displays authentication sequence as
it occurs
[debug] ppp [authentication]
Configuring Frame Relay
Specifies encapsulation type.
encapsulation frame-relay
[cisco | ietf]
Specifies LMI type used by the FR
switch. (default cisco)
frame-relay lmi-type ansi |
cisco | q933i
Inverse ARP is enabled by default.
If it has been disabled use this
command to enable it.
frame-relay inverse-arp
[protocol] [dlci]
Used to define the address to DLCI
table statically.
frame-relay map protocol protocoladdress
dlci [broadcast] [ietf | cisco ]
Displays the route maps (static or
dynamic)
show frame-relay map
Displays LMI information show frame-relay lmi
Selects a subinterface to configure interface serial
number.subinterface-number
multipoint | point-to-point
Defines the local DLCI number being
linked to the interface
frame-relay interface-dlci dlcimumber
Misc. Commands
Remove 10 minute interval router
waits for input
no exec-timeout or exec-timeout 0 0
Set clock clock set 20:26:00 04 July 2001
Change number of lines history will
record (max 256)
terminal history size “lines”
Sets token ring speed to 16 Mbps ring-speed 16
Enables early token release early-token release
Specifies a media independent
interface physical connection
media-type 10baseT
set the configuration register
(where to boot from) 0 for
ROM Monitor, 1 for ROM, 2 NVRAM.
config-register 0x2102
