Network Fundamentals: Ch11 - Configuring and Testing your Network

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Network Fundamentals

CH11: CONFIGURING AND TESTING YOUR NETWORK

Abdelkhalik Elsaid Mosa

abdu.elsaid@yahoo.com

http://abdelkhalik.staff.scuegypt.edu.eg/

Suez Canal University – Faculty of Computers & Informatics - Cisco Local Academy

What is a Router?

• Front View

• Rear View

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What is a Router?

Router is a computer which consists of

H/W S/W

CPU InterfacesMemory IOS Config File

Flash NVRAM RAM ROM LAN WANManagement

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Router’s Memory

• RAM «volatile»: used to store1. Running version of IOS.2. Running config. File.3. Routing table.4. ARP Cache «is used on routers that have LAN interfaces».5. Packet Buffer.

• ROM «permanent»: used to store1. POST, Basic diagnostic software.2. Bootstrap.3. Scaled down Version of IOS «Rxboot».4. ROMMon.

• Flash «Non volatile»: used to store IOS.• NVRAM: used to store Start Up Configuration.

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Router Boot-up Process

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Router’s Interfaces

• Router Interfaces: capable of sending and receiving traffic. 1. LAN 2. WAN• Management Ports: used for administrative access.1. Console2. AUX

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Cisco IOS - Access Methods

• The most usual methods are:1. Console: Doesn’t require active networking services.2. AUX port: Doesn’t require active networking services.3. Telnet or SSH: Requires active networking services.

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Console Port

• Examples of console use are: The initial configuration of the network deviceDisaster recovery procedures and troubleshooting where

remote access is not possible.Password recovery procedures.

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Using HyperTerminal

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Auxilary Port

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Cisco IOS Modes

• Cisco IOS is a Modal OS.• In order from top to bottom, the modes are:

1. Setup mode.2. User executive mode “view only mode”3. Privileged executive mode “enable mode”4. Global configuration mode5. Other specific configuration modes

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Setup mode

• Permit admin to install a minimal configuration for a router.• The router will enter setup mode when:

Contents of NVRAM erased “erase startup” command. When the router is “out of the box”.

• You can make the router enter setup mode by entering: Router# setup

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User executive mode

• Allows only a limited number of basic monitoring commands. • Often referred to as a “view only” mode. • Does not allow any commands that might change the

configuration of the router. • Identified by the > prompt.

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Privileged executive mode

• Provides access to all router commands. • This mode can be configured to require a password. • Global configuration mode and all other more specific

configuration modes can only be reached from the privileged EXEC mode.

• The privileged EXEC mode can be identified by the # prompt.

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Global configuration & Specific Configuration

• Configuration changes are made that affect the operation of the device as a whole.

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Basic IOS command structure

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Using CLI help

• The IOS has several forms of help available:1. Context-sensitive help2. Command Syntax Check3. Hot Keys and Shortcuts

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Context-sensitive help

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Command Syntax Check

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Hot Keys and Shortcuts

• Tab: Completes the remainder of the command or keyword.• Ctrl-R: Redisplays a line• Ctrl-Z: Exits configuration mode and returns to the EXEC.• Down Arrow: Scroll forward through former commands.• Up Arrow: Scroll backward through former commands• Ctrl-Shift-6: Interrupt an IOS process such as ping or tracert.• Ctrl-C: Aborts the current command and exits the

configuration mode.• Abbreviated commands: Commands can be abbreviated to

the minimum number of characters that identifies a unique selection. Ex: sh int = show interfaces

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IOS examination commands

• Show version• Show flash• Show interfaces• Show startup-config• Show running-config

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Basic Router Configuration

• Naming the router: Host name should be unique.

• Banner: Banner should warn against unauthorized use.

• Passwords: Use strong passwords• Privileged mode password

• Console Password

• Telnet Password

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Basic Router Configuration

• Interface configurations: interface type, IP address and subnet mask. Describe purpose of interface. Issue no shutdown command. If DCE serial issue clock rate command.

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Configuring a serial interface

S0/0S0/1

192.168.1.1/30192.168.1.2/30

RouterA(config)# interface serial 0/0RouterA(config-if)# ip address 192.168.1.1 255.255.255.0RouterA(config-if)# no shutdownRouterA(config-if)# clock rate 56000 (required for serial DCE only)RouterA(config-if)# exit

RouterB(config)# int serial 0/1 RouterB(config-if)# ip address 192.168.1.2 255.255.255.252RouterB(config-if)# no shutdownRouterB(config-if)# exitRouterB(config)# exitRouter#

To know which interface is the DCE :RouterA# show controller s0/0

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Interpreting the Interface Status

• Other Interface Status• Serial0/1 is administratively down , line protocol is down

interface is shut down • Serial0/1 is down , line protocol is down

interface or cable H/W failure ( no keep-alives )• Serial0/1 is up , line protocol is down

different encapsulation type ( PPP , HDLC , FR ) or no clock rate on DCE.

Layer 1 status Layer 2 status

Interface is working properly

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Just Refresh – Enable Mode commands

• copy running-config startup-config• copy startup-config running-config• erase startup-config• ping ip_address• traceroute ip_address• show interfaces• show version• show arp• show startup-config• show running-config• show ip interface brief • configure terminal• show controllers serial_interface

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Thank You..