Tuesday, September 8, 2009

Router Commands Overview

In this section you will learn about the router commands, configurations, privileged mode commands, routing protocols, cisco labs and network configurations.
There are hundreds of basic and advance level commands of a router. It is not easy to remember all the commands. But some commands are frequently used and can be remembered with some practice. I have provided a list of the most commonly used commands based on their features and usage.

You will find here some basic terminology of a router.

Routing: Routing is a process of moving the data (packets) through an inter network. Routing performs the two basic tasks. Define the paths for a packet and then forward the packets on the basis of defined paths. Routing can also be defined as the communication between two or more logically and physical networks and this communication (packet transfer) is brought by a router.

First of all you should remember the keyboard shortcuts of a router.

Keyboard Shortcuts

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

Configuring the Router
You will be able to learn the basic commands for configuring a router.

sh running-config - details the running configuration file (RAM)

sh startup-config - displays the configuration stored in NVRAM

setup - Will start the 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 config in running config (RAM) to NVRAM or "write memory" for IOS under ver.11

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

boot system flash - 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

boot system rom - tell 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
Here is a list of the general commands.

These are the basic level commands and most commonly used

no shutdown - (enables the interface)reload - restarts the router

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

sh clock - shows date and time on routersh 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 router

sh protocols - shows which protocols are configured

banner motd # Your customized message here # - Set/change banner

hostname - use to configure the hostname of the router

clear counters - clear interface counters

Privileged Mode commands of a router
Learn how to work in the privileged mode of a router.

enable - get to privileged modedisable - get to user mode

enable password - sets privileged mode password

enable secret - sets encrypted privileged mode password

Setting Passwords on router

Here you will be able to learn how to set the password on a router.

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

Setting the password for console access:
(config)#line console 0



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

(config)#line vty 0 4



Set password for auxiliary (modem) access:

(config)#line aux 0



Router Processes & Statistics
By these command you can see the statistics and different processes of the router.

sh processes - shows active processes running on 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 reason for last reboot, monitors the stack use of processes and interrupts routines

IP Commands
Here is a list of the 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 [administrative_distance] - configure a static IP route

ip route - sets default gatewayip 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 interfacesh ip protocol

CDP Commands (Cisco Discovery Protocol uses layer 2 multicast 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 specific interface

sh cdp entry - shows CDP neighbor detailc

dp 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 entire router (global config)

no cdp enable - turns off CDP on specific interface

IPX Commands
Enable IPX on router:

ipx routing

Configure IPX + IPX-RIP on an int:

int ser 0ipx 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
RIP, IGPR and OSPF are the routing protocols and here is a list of the commands for the working on the 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
Here is a list of the Access list command of a router.

sh ip int ser 0 - use to view which IP access lists are applies to which int

sh ipx int ser 0 - use to view which IPX access lists are applies to which int

sh appletalk int ser 0 - use to view which AppleTalk access lists are applies to which intView 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

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 host eq 23

access-list 100 deny tcp any eq 80

int eth 0ip 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 0ipx 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 Commands
Networking over WAN is the main functionality of a router. The most common use of a router is for the WAN connectivity. Here is a list of the commands for the different methods of the WAN connectivity.

PPP Configuration
Point to point protocol is a method for the WAN connectivity and you will find here some commands of PPP.

encapsulation pppppp authentication

ppp chap hostname

ppp pap sent-username

sh int ser 0 - use to view encapsulation on the interface

Frame-Relay Configuration
One of the methods for the WAN connectivity is the Frame Relay. Find here some basic commands for the WAN connectivity through Frame Relay.
Encapsulation frame-relay ietf - use IETF when setting up a frame-relay network between a Ciscorouter 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)

Keep alive 10 - use to set keep alive

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 mapssh frame-relay lmi - shows LMI info

Miscellaneous Commands
In the last but not least here is a list of the some miscellaneous and useful commands

sh controller t1 - shows 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)

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