Chapter 2

Router Configuration

ContentsRouter simulationIntroduction to Mode of routerThe Command to change Mode of routerBasic CommandTelnetDHCP ServerDNS Server

Router simulationGNS3Boson NetSim Network Visualizer

Introduction to Mode of routerRouter Mode has 3 types:

◦User Mode: indicated by > prompt that allow you look at some of router setting.

◦Privilege Mode: indicated by # prompt that use to display all of router setting.

◦Configuration Mode: is used to configure router.◦Interface Mode: is used to configuration of a

specific interface of router.

The Command to change Mode of routerEnableDisableConfigure TerminalEndExitInterface

Basic Command Show:

◦ Version: ◦ Protocols: View Layer3 for all interface currently configure on router.◦ Flash: ◦ History: display history command◦ Running-Config: ◦ Clock: display clock◦ Hosts: show list of hostname was created on router◦ Users: display user who are connect to router◦ Interfaces: display static of all interfaces configure on router◦ CDP Interface : display status of all interface are running CDP Protocol◦ CDP Neighbors: provide information about directly connected neighbors◦ CDP Neighbors Detail : provide detail information about directly connected neighbors◦ CDP: show how often CDP update are being sent and how long recipient should retain update

Test network connectivity:◦ Ping◦ Tracert

Naming Router◦ HostName

Basic CommandCDP Timer: adjust the number of second

between CDP Update.CDP HoldTime: adjust the hold timer to secondNo CDP Run: disable CDP for entire routerNo CDP Run enable: disable CDP for only

interface

Basic CommandBasic IP Configuration and verification

◦ IP Address: to add IP Address to a specific interface◦No Shut: active interface◦Shutdown: shutdown interface◦Clock Rate: set clock rate on serial line interface◦Show IP Interface Brief: view the IP address on interface.◦Description: comment on interface◦HostName: set hostname for router.◦Copy Running-Config Startup-Config: save running

config.

Basic Command CDP: allow you to view information operation information version, Protocol

information, and much more Global configuration command:

◦ No cdp run: turn off for entire router◦ Cdp run: turn on for entire router◦ Cdp timer: configure cdp advertise for every time you specific

Interface configuratio command:◦ Cdp enable: turn cdp for the inerface◦ No Cdp enable: turn off cdp for the interface

Show command:◦ Show cdp interface: display interface setting◦ Show cdp neighbor: display directly connected neighbor◦ Show cdp neighbor detial: display detail information about neighbor◦ Show cdp: display general information

ARP command:◦ Show ARP: Display ARP Table◦ Clear ARP: To clear ARP Table

TelnetCommand used to configure Telnet

◦ Configure◦ Line◦ Interface◦ Password◦ Login

To enable telnet on router we follow these steps:◦ Step 1: go to Configuration mode (Configure Terminal)◦ Step 2: set IP address on Network port( ◦ Step 3: Change to VTY interface (line VTY 0 4)◦ Step 4: Create password for telnet login ( password pwd, login)◦ Step 5: Create configuration password( enable password pwd)◦ Step 6: Run Telnet from Client PC( Telnet IP address/dns name)

DHCP Server This Cisco IOS DHCP Server feature is

supported on the following routers and access servers:◦ Catalyst 5000 family switches with an installed

Route Switch Module◦ Catalyst 6000 family switches with an installed

MultiLayer Switch Feature Card◦ Catalyst 8500 series◦ Cisco 800 series◦ Cisco 1000 series◦ Cisco 1400 series◦ Cisco 1600 series◦ Cisco 1700 series (support for the Cisco 1700 series

was added in Cisco IOS Release 12.0[2]T)◦ Cisco 2500 series◦ Cisco 2600 series◦ Cisco 3600 series◦ Cisco 3800 series◦ Cisco MC3810 series

◦ Cisco 4000 series◦ Cisco AS5100 access server◦ Cisco AS5200 universal

access server◦ Cisco AS5300 universal

access server◦ Cisco 7000 series◦ Cisco 7100 series◦ Cisco 7200 series◦ Cisco MGX 8800 with an

installed Route Processor Module

◦ Cisco 12000 series◦ Cisco uBR900 series◦ Cisco uBR7200 series

Command use for configure DHCP ServerCommand PurposeRouter(config)# ip dhcpexcluded-address low-address[high-address]

Specifies the IP addresses that the DHCP server should notassign to DHCP clients.

Router(config)# ip dhcp pool name Creates a name for the DHCP server address pool and placesyou in DHCP pool configuration mode

Router(config-dhcp)# networknetwork-number [mask | /prefix-length]

Specifies the subnet network number and mask of the DHCPaddress pool.

Router(config-dhcp)# dns-server address[address2 ... address8]

Specifies the IP address of a DNS server that is available to aDHCP client.

Router(config-dhcp)# default-routeraddress [address2 ... address8]

Specifies the IP address of the default router for a DHCP client.

Router(config-dhcp)# lease {days[hours][minutes] | infinite}

Specifies the duration of the lease.

Router(config)# service dhcp Enables the Cisco IOS DHCP Server feature on your router.

Configuring Manual Bindings

Monitoring and Maintaining the DHCP Server

DNS Server DNS Overview:

◦ Hostnames for Network Devices: The DNS system can locate a network device by translating the hostname of the device into its associated IP address.

◦ Domains Names for Groups of Networks: IP defines a naming scheme that allows a device to be identified by its location in the IP.

◦ Name Servers: Name servers are programs that have complete information about their namespace portion of the domain tree and may also contain pointers to other name servers that can be used to lead to information from any other part of the domain tree.

◦ Cache: The cache stores the results from previous responses.◦ Name Resolvers: Name resolvers are programs that extract information from name

servers in response to client requests.◦ Zones: A zone contains all domains from a certain point downward, except those for

which other zones are authoritative. How to Configure DNS

◦ Mapping Hostnames to IP Addresses◦ Configuring the Router as a DNS Server

Mapping Hostnames to IP AddressesStep:

1. enable2. configure terminal3. ip host name [tcp-port-number] address1 [address2 ...

address8]4. ip domain name name or ip domain list name5. ip name-server server-address1 [server-address2 ... server-

address6]6. ip domain lookup [source-interface interface-type interface-

number]

Example

Example (Continue)

Configuring the Router as a DNS Server STEPS:

1. enable2. configure terminal3. ip dns server4. ip name-server server-address1 [server-address2 ... server-address6]5. ip dns server queue limit {forwarder queue-size-limit | director queue-size-

limit}6. ip host [vrf vrf-name] [view view-name] hostname {address1 [address2 ...

address8] |additional address9 [address10 ... addressn]}7. ip dns primary domain-name soa primary-server-name mailbox-name

[refresh-interval[retry-interval[expire-ttl [minimum-ttl]]]]8. ip host domain-name ns server-name

Example

Example (Continue)

Verifying DNS