Cisco IOS Commands

February 17, 2019 (Last Modified: May 06, 2020)

Fadıl

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> – s et 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:

    (config)#line console 0
    (config-line)#login 
    (config-line)#password <password_here>

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

   (config)#line vty 0 4 
    (config-line)#login 
    (config-line)#password <password_here>

Set password for auxiliary (modem) access:

    (config)#line aux 0
    (config-line)#login 
    (config-line)#password <password_here>

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
boo t 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

(config-if)#clock rate 6400 - set clock on DCE (bits per second)
(config-if)#bandwidth 64 - set bandwidth (kilobits)

IP Commands

Configure IP on an interface:
int serial 0
ip address 157.89.1.3 255.255.0.0
int eth 0
ip address 2008.1.1.4 255.255.255.0

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 0.0.0.0 0.0.0.0 <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 2.2.2.2 255.255.255.0 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
network 157.89.0.0
network 208.1.1.0 Other RIP Commands: debug ip rip – view RIP debugging info
Configure IGRP:
router IGRP 200
network 157.89.0.0
network 208.1.1.0 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:

sh access-lists
sh ip access-lists
sh ipx access-lists
sh appletalk access-lists
Apply standard IP access list to int eth 0:
access-list 1 deny 200.1.1.0 0.0.0.255
access-list 1 permit any
int eth 0
ip access-group 1 in
Apply Extended IP access list to int eth 0:
access-list 100 deny tcp host 1.1.1.1 host 2.2.2.2 eq 23
access-list 100 deny tcp 3.3.3.0 0.0.0.255 any eq 80
int eth 0
ip access-group 100 out
Apply Standard IPX access list to int eth 0:
access-list 800 deny 7a 8000
access-list 800 permit -1
int eth 0
ipx access-group 800 out
Apply Standard IPX access list to int eth 0:
access-list 900 deny sap any 3378 -1
access-list 900 permit sap any all -1
int eth 0
ipx access-group 900 out

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 3.3.3.3 100 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