Configuring a Router Module 3 Semester 2

Router Configuration Tasks Name a router Set passwords Examine show commands Configure a serial interface Configure an Ethernet interface Execute changes to a router Save changes to a router Configure an interface description Configure a message-of-the-day banner Configure host tables Understand the importance of backups and documentation

Router Modes All configuration changes are made from Global Config mode Ctrl-Z or end –returns to Privileged EXEC mode exit –Go back one step

Configure Hostname Required if name resolution is to be used Not essential for the functioning of our routers but is important

Configuring passwords An important feature –security –telnet (vty) will not work without a password set Line console 0 –sets login password for User EXEC mode Enable password xxx –sets login password for Privileged EXEC mode Enable secret –sets encrypted password for Privileged EXEC mode –(strong encryption)

Show Commands show interfaces – Displays statistics for all interfaces on a router. –Router#show interfaces serial 0/1 show controllers serial - Displays information that is specific to the interface hardware. This command must also include the port or slot/port number of the serial interface. –Router#show controllers serial 0/1 show clock - Shows the time set in the router show hosts - Displays a cached list of host names and addresses show users - Displays all users who are connected to the router show history - Displays a history of commands that have been entered show flash - Displays information about flash memory and what IOS files are stored there show version - Displays information about the currently loaded software version along with hardware and device information show arp - Displays the ARP table of the router show protocols - Displays the global and interface-specific status of any configured Layer 3 protocols show startup-config - Displays the saved configuration located in NVRAM show running-config

Configuring an interface

Configuring an Ethernet Interface

Configuring a Serial Interface Fast Ethernet Interface Router(config)# interface fastethernet 0/0 Router(config-if)# ip address Router(config-if)# no shutdown Serial Interface (DCE)(no clock for DTE) Router(config)# interface serial 0/0 Router(config-if)# ip address Router(config-if)# clock rate Router(config-if)# no shutdown

Configuring Interface Descriptions An interface description should identify important information such as a router, a circuit number, or a specific network segment.

The Login Banner The Banner is seen when someone attempts to login Important to let user know it is a private system

Login Banner MOTD Configured from Global Config mode Use the Banner MOTD command Use delimiters (#) to indicate start and end of message

Host Name Resolution Two Choices –DNS Dynamic (not available in our lab) –Hosts Table Static entries Used in our lab situation

Configuring Hosts Tables The Host table contains: –Name –IP address of each router in the network The host name in a command will be resolved to an IP address if the name is found in the table –i.e. ping Auckland –is translated to ping (if the hosts below entered) Host tables only apply to the the local router

The copy running-config tftp Command Backing up Configuration Files

The copy tftp running-config Command Restoring Configuration Files from a TFTP Server

Changing Router Configuration

Configuration Standards Configuration Standards may specify: –How the files are stored –Where the files are stored –Naming conventions –Who has access –Coding standards – e.g. comments, sections, etc –Interface descriptions

TUGAS-sImple Example Your network can now have 255 /16 subnets with 65,534 hosts each AND 256 /24 subnets with 254 hosts each. All you need to make it work is a classless routing protocol that passes the subnet mask with the network address in the routing updates. Classless routing protocols: RIPv2, EIGRP, OSPF, IS-IS, BGP Subnets / / / / / /24 Etc / /16 Etc / /16 An example of VLSM, NOT of good network design / / / / / / / / / / / / /24