Configuring a Router

1. Configuring a Router Module 3 Semester 2

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

3. 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

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

5. 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)

6. 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 Show Commands

7. Configuring an interface

8. Configuring an Ethernet Interface

9. Fast Ethernet Interface Router(config)# interface fastethernet 0/0 Router(config-if)# ip address 190.100.11.1 255.255.255.0 Router(config-if)# no shutdown Serial Interface (DCE) (no clock for DTE) Router(config)# interface serial 0/0 Router(config-if)# ip address 190.100.10.2 255.255.255.0 Router(config-if)# clock rate 56000 Router(config-if)# no shutdown Configuring a Serial Interface

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

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

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

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

14. 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 172.16.32.1 (if the hosts below entered) • Host tables only apply to the the local router

15. The copy running-config tftp Command Backing up Configuration Files

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

17. Changing Router Configuration

18. 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