Cisco Commands

no shutdown

(enables the interface)

What is the Administrative Distance of a directly connected interface?

0

What is the Administrative Distance of a statically assigned IP Route?

1

What is the Administrative Distance of an unknown route?

255

Refresh screen output

<Ctrl-R>

Suspend or abort

<Shift> and <Ctrl> and 6 then x

sh ver

Cisco IOS version, uptime of router, how the router started, where system was loaded from, the interfaces the POST found, and the configuration register

copy flash tftp

Copies flash to tftp server

copy run tftp

Copies the current running-config to tftp server

disable

Disables privileged EXEC level

Name the 2 types of Interior Routing Protocols

Distance Vector and Link State.

Name 2 Exterior Gateway Protocols

EGP (Exterior Gateway Protocol) and BGP (Border Gateway Protocol)

What happens during a Store and Forward operation?

Entire frame is copied into the buffer and checked for CRC errors before forwarding. Higher latency.

exit

Exits back to global configuration level

exit

Exits out of configuration level

Exit Router

Logout or exit or quit

Name 4 Link State Routing Protocols

OSPF - decisions based on cost of route (metric limit of 65,535); EIGRP - hybrid protocol (both Distance-Vector and Link State), Cisco proprietary; NLSP; and IS-IS

What happens during a cut-through operation?

Only the destination address is read into the buffer, and it forwards immediately. Low latency; "wire-speed"

Name 3 Distance Vector Routing Protocols

RIP - 15 hop count max; IGRP - 255 hop count max, uses reliability factor (255 optimal), and bandwidth; RTMP

no ip address

Removes IP address

copy tftp flash

Restores flash from tftp server

copy tftp run

Restores the running-config from tftp server

banner motd # Your_message #

Set/change banner

interface ethernet0

Switches to configure the ethernet0 interface

configure terminal

Switches to global configuration level

enable

Switches to privileged EXEC level

Compleat Command

TAB

What do Virtual LAN's do?

They set different ports on a switch to be part of different sub-networks. Benefits include simplifying moves, adds, and changes; reducing administrative costs; having better control of broadcasts; tightening security; and distributing load.

Why was Spanning Tree Protocol developed?

To prevent routing loops. It uses the Spanning-Tree Algorithm to calculate a loop-free network topology that allows redundant paths without suffering the effects of loops in the network

Link State Routing Protocols

Understand the entire network, and do not use secondhand information. Routers exchange LSP's (hello packets). Each router builds a topographical view of the network, then uses the SPF (shortest path first) algorithm to determine the best route. Changes in topology can be sent out immediately, so convergence can be quicker.

Distance Vector Routing Protocols

Understands the direction and distance to any network connection on the internetwork. Knows how many hops (the metric) to get there.

setup

Will start the the automatic setup; the same as when you first boot the router

Interior Routing Protocols

Within an autonomous system - AS - group of routers under the same administrative authority

cdp timer 120

change how often CDP info is sent (default cdp timer is 60)

clear counters

clear interface counters

copy startup-config running-config

copies from non-volatile (NVRAM) to current running config (RAM)

copy running-config startup-config

copies saved config in running config (RAM) to NVRAM or "write memory" for IOS under ver.11

Backup the IOS onto a TFTP server

copy flash tftp

Copy DRAM configuration to a TFTP server

copy runing-config tftp

Save the current configuration from DRAM to NVRAM

copy running-config startup-config

Merge NVRAM configuration to DRAM

copy startup-config running-config

Upgrade the router IOS from a TFTP server

copy tftp flash

Merge TFTP configuration with current router configuration held in DRAM

copy tftp runing-config

sh flash

describes the flash memory and displays the size of files and the amount of free flash memory

sh running-config

details the running configuration file (RAM)

Return to user mode from privileged

disable

sh buffers

displays statistics for router buffer pools; shows the size of the Small, Middle, Big, Very Big, Large and Huge Buffers

sh startup-config

displays the configuration stored in NVRAM

Recall next command

down arrow or <Ctrl-N>

config mem

executes configuration commands stored in NVRAM; copies startup-config to running-config

enable

get to privileged mode

disable

get to user mode

cp holdtime 240

how long to wait before removing a CDP neighbor (default CDP holdtime is 180)

reload

restarts the router

enable secret <password_here>

set encrypted password for privilegedaccess

enable password <password_here>

set password for privileged access (used when there is no enable secret and when using older software)

enable secret <password_here>

sets encrypted privileged mode password

enable password <password_here>

sets privileged mode password

sh cdp int eth 0/0

show CDP info for specific interface

Display access lists, this includes the number of displayed matches

show access-lists

Display detailed information on all devices

show cdp entry *

Display a summary of connected cdp devices

show cdp neighbor

View type of serial cable on s0

show controllers 0 (note the space between the 's' and the '0')

Show IOS file and flash space

show flash

show lmi traffic stats

show frame-relay lmi

Display the frame inverse ARP table

show frame-relay map

Check a Frame Relay PVC connections

show frame-relay pvc

View the interface status of interface e0

show interface e0

Overview all interfaces on the router

show ip interfaces brief

Display current routing protocols

show ip protocols

Display IP routing table

show ip route

Check the router can see the ISDN switch

show isdn status

Shows all logs that the router has in its memory

show log

View current configuration (DRAM)

show running-config

View startup configuration (NVRAM)

show startup-config

View version information

show version

sh cdp entry <cdp_neighbor_here>

shows CDP neighbor detail

sh processes

shows active processes running on router

sh debug

shows all debugging that is currently enabled

sh process cpu

shows cpu statistics

sh clock

shows date and time on router

sh cdp neighbor

shows directly connected neighbors

sh cdp run

shows if CDP turned on

sh mem

shows memory statistics

sh stacks

shows reason for last reboot, monitors the stack use of processes and interrupts routines

sh history

shows the history of your commands

sh users

shows users connected to router

sh cdp int

shows which interfaces are running CDP

sh protocols

shows which protocols are configured

boot system rom

tell router to boot from ROM at next boot

boot system flash <filename_here>

tells router which IOS file in flash to boot from

boot system tftp

tells router which IOS file on the tftp server to boot from

no cdp run

turns off CDP for entire router (global config)

no cdp enable

turns off CDP on specific interface

no debug all

turns off all debugging

Recall last command

up arrow or <Ctrl-P>

hostname <router_name_here>

use to configure the hostname of the router

config t

use to execute configuration commands from the terminal

config net

used to retrieve configuration info from a TFTP server