Cisco IOS Commands

Privileged Mode

enable – get to privileged mode
disable – get to user mode
enable password <password_here> – sets privileged mode password
enable secret <password_here> – sets encrypted privileged mode password

Setting Passwords

enable secret <password_here> – set encrypted password for privileged access
enable password <password_here> 
– set password for privileged access (used when there is no enable secret and when using older software)
Set password for console access:

Set password for virtual terminal (telnet) access (password must be set to access the router through telnet):

Set password for auxiliary (modem) access:


Configuring the Router

sh running-config – 
details the running configuration file (RAM)
sh startup-config – 
displays the configuration stored in NVRAM
setup – Will start the automatic setup; the same as when you first boot the router
config t – use to execute configuration commands from the terminal
config mem – executes configuration commands stored in NVRAM; copies startup-config to running-config
config net – used to retrieve configuration info from a TFTP server
copy running-config startup-config – copies saved the config in NVRAM to running-config (RAM)
copy startup-config running-config – copies current running-config (RAM) to non-volatile (NVRAM)
boot system flash <filename_here> – tells the router which IOS file in flash to boot from
boot system tftp – tells the router which IOS file on the TFTP server to boot from
boot system rom – tell the router to boot from ROM at next boot
copy flash tftp – Copies flash to TFTP server
copy tftp flash – Restores flash from TFTP server
copy run tftp – Copies the current running-config to TFTP server
copy tftp run – Restores the running-config from TFTP server


General Commands

no shutdown – (enables the interface)
reload – restarts the router
sh ver
– Cisco IOS version, the uptime of router, how the router started, where the system was loaded from, the interfaces the POST found, and the configuration register
sh clock – shows date and time on the router
sh history – shows the history of your commands
sh debug – shows all debugging that is currently enabled
no debug all – turns off all debugging
sh users – shows users connected to the router
sh protocols – shows which protocols are configured
banner motd # Your_message # – Set/change banner
hostname <router_name_here> – use to configure the hostname of the router
clear counters  – clear interface counters


Processes & Statistics

sh processes – shows active processes running on the router
sh process cpu 
– shows CPU statistics
sh mem 
– shows memory statistics
sh flash – describes the flash memory and displays the size of files and the amount of free flash memory
sh buffers – displays statistics for router buffer pools; shows the size of the Small, Middle, Big, Very Big, Large and Huge Buffers
sh stacks – shows the reason for the last reboot, monitors the stack use of processes and interrupts routines


CDP Commands (Cisco Discovery Protocol uses layer 2 multicasts over a SNAP-capable link to send data):

sh cdp neighbor – shows directly connected neighbors
sh cdp int – shows which interfaces are running CDP
sh cdp int eth 0/0 – show CDP info for a specific interface
sh cdp entry <cdp_neighbor_here> – shows CDP neighbor detail
cdp timer 120 – change how often CDP info is sent (default CDP timer is 60)
cp holdtime 240 – how long to wait before removing a CDP neighbor (default CDP holdtime is 180)
sh cdp run – shows if CDP turned on
no cdp run – turns off CDP for an entire router (global config)
no cdp enable – turns off CDP on a specific interface


Miscellaneous Commands

sh controller t1 
– shows the status of T1 lines
sh controller serial 1 – use to determine if DCE or DTE device


IP Commands

Configure IP on an interface:
    int serial 0
ip address
int eth 0
ip address 2008.1.1.4

Other IP Commands:

    sh ip route – view ip routing table
    ip route <remote_network> <mask> <default_gateway> [administrative_distance] – configure a static IP route
   ip route <gateway_of_last_resort> – sets default gateway
  ip classless – use with static routing to allow packets destined for unrecognized subnets to use the best possible route
    sh arp – view arp cache; shows MAC address of connected routers
ip address secondary – configure a 2nd IP address on an interface
    sh ip protocol


IPX Commands

Enable IPX on the router:
    ipx routing
Configure IPX + IPX-RIP on an int: 

    int ser 0
ipx network 4A

Other Commands:

sh ipx route 
– shows IPX routing table
    sh ipx int e0 – shows IPX address on int
    sh ipx servers – shows SAP table
    sh ipx traffic – view traffic statistics
    debug ipx routing activity – debugs IPS RIP packets
    debug ipx sap – debugs SAP packets

Routing Protocols

Configure RIP:
    router rip
Other RIP Commands: 
debug ip rip
 – view RIP debugging info
Configure IGRP:
    router IGRP 200
Other IGRP Commands:
    debug ip igrp events – view IGRP debugging info
    debug ip igrp transactions – view IGRP debugging info


Access Lists

sh ip int ser 0 – use to view which IP access lists are applied to which int
sh ipx int ser 0 – 
use to view which IPX access lists are applied to which int
sh appletalk int ser 0 – 
use to view which AppleTalk access lists are applied to which int

View access lists:


Wan Configurations

PPP Configuration

encapsulation ppp
ppp authentication <chap_or_pap_here>
ppp chap hostname <routername_here>
ppp pap sent-username <username_here>
sh int ser 0 –
 use to view encapsulation on the interface


Frame-Relay Configuration

encapsulation frame-relay ietf – use IETF when setting up a frame-relay network between a Cisco router and a non-Cisco router
frame-relay lmi-type ansi – LMI types are Cisco, ANSI, Q933A; Cisco is the default; LMI type is auto-sensed in IOS v11.2 and up
frame-relay map ip 100 broadcast – if inverse ARP won’t work, map Other IP to Your DLCI # (local)
keepalive 10 – use to set keepalive
sh int ser 0 – use to show DLCI, LMI, and encapsulation info
sh frame-relay pvc – shows the configured DLCI’s; shows PVC traffic stats
sh frame-relay map – shows route maps
sh frame-relay lmi – shows LMI info


Keyboard Shortcuts

CTRL-P – show the previous command
CTRL-N – show next command
SHIFT-CTRL-6 – Break