Module 02 Cisco IOS Chapter 09 Basic Router Configuration and Operation Table of Content Configuring IP Addresses IP Troubleshooting Features CONFIGURING IP ADDRESSES CONFIGURING IP ADDRESSES Router#configure terminal Router(config)#interface type slot/port Router(config-if)#ip address Router(config-if)#no shutdown Configuring an Ethernet interface Router# configure terminal Router(config)# interface ethernet 0/0 Router(config-if)# ip address Router(config-if)# no shutdown Configuring interface description Router# configure terminal Router(config)# interface type slot/port Router(config-if)# description xyz Configure Habitually On Routers  The exec timeout minutes seconds command sets the inactivity timeout  The logging synchronous line subcommand tells the router not to interrupt the output of a show command with these unsolicited messages, letting you read the output of the command that you typed before the router displays the other messages SHOW IP ROUTE command SHOW IP PROTOCOLS command Troubleshooting using show controllers serial 10 Destination unreachable I don not know How to get to Z! Send ICMP Send Data To Z A C Data network To Z Destination unreachable • An ICMP destination unreachable message is send if: −Host or port unreachable −Network unreachable 15 Destination unreachable message Type(3) 16 Code(0-12) 31 Checksum Unused (must be zero) Internet Header + First 64 bits of datagram • The value of in the type field indicates it is a destination unreachable message • The code value indicates the reason the packet could not be delivered 16 Code values for destination unreachable message Code Description Net unreachable Host unreachable Protocol unreachable Port unreachable Fragmentation needed and DF set Source route failed Destination network unknown Destination host unknown Source Host Isolated Communication with destination network administratively prohibited 10 Communication with destination network administratively prohibited 11 Network unreachable for type of device 12 Host unreachable for type of device 17 Using ping to test destination reachability Yes, I am here Is B reachable A A B C ICMP echo request ICMP echo reply 18 ICMP echo messages Type (0 or 8) 16 Code (0) Identifier 31 Checksum Sequence number Option Data … • The value of in the type field indicates it is the echo request • The value of in the type field indicates it is the echo reply 19 Detecting excessively long routes •When the TTL of the datagram value reaches zero, the packet is discarded •ICMP uses a time exceeded message to notify the source device that the TTL of the datagram has been exceeded 20 ICMP Type of Control messages Type Description Echo reply Destination unreachable Source quench Redirect / Change request Echo Request Routers advertisment 10 Router Selection 11 Time exceeded 12 Parameter problem 13 Timestamp 14 Timestamp reply 15 Information Request 16 Information Reply 17 Address Mask Request 18 Address Mask Reply • Unlike error messages, control messages are used to inform hosts of conditions such as network congestion or the existence of a better gateway to a remote network • Like all ICMP messages, ICMP control messages are encapsulated within an IP datagram • ICMP uses IP datagrams in order to traverse multiple networks 21 Telnet operation LAB_A Show sessions Disconnect Telnet LAB_B Connect LAB_B Ctrl-Shift-6 x Enter Exit LAB_B 22 Introduction to CDP 23 Information obtained with CDP  Device ID  Local Interface  Holdtime  Capability  Platform  Port ID  VTP Management Domain Name (CDPv2 only)  Native VLAN (CDPv2 only)  Full/Half-Duplex (CDPv2 only) 24 CDP Configuration Commands LAB_A#configure terminal Enter configuration commands, one per line LAB_A(config)#cdp run LAB_A(config)#cdp timer 60 LAB_A(config)#cdp holdtime 180 End with CNTL/Z LAB_A(config)#interface ethernet LAB_A(config-if)#no cdp enable LAB_A(config-if)#exit LAB_A(config)#exit LAB_A# 25 Show cdp interface Serial0 is down, line protocol is down Encapsulation HDLC Sending CDP packets every 60 seconds Holdtime is 180 seconds Serial1 is administratively down, line protocol is down Encapsulation HDLC Sending CDP packets every 60 seconds Holdtime is 180 seconds 26 Show cdp neighbor Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - Repeater Device ID SCA0425051J Switch Local Intrfce Fas 0/24 Fas 0/23 Holdtme 158 147 apability T S T S latform PortID WS-C6509 3/20 WS-C2924-XFas 0/24 27 Show cdp entry * Device ID: SCA0425051J Entry address(es): IP address: 192.168.4.254 Platform: WS-C6509, Capabilities: Trans-Bridge Switch Interface: FastEthernet0/24, Port ID (outgoing port): 3/20 Holdtime : 138 sec Version : WS-C6509 Software, Version McpSW: 5.4(2) NmpSW: 5.4(2) Copyright (c) 1995-2000 by Cisco Systems advertisement version: VTP Management Domain: 'SSP' Native VLAN: 20 Duplex: full Device ID: Switch Entry address(es): Platform: cisco WS-C2924-XL, Interface: FastEthernet0/23, Holdtime : 127 sec Capabilities: Trans-Bridge Switch Port ID (outgoing port): FastEthernet0/24 28 Summary      Basic router configuration ICMP PING TELNET CDP 29 ... 180 seconds 26 Show cdp neighbor Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - Repeater Device ID SCA0425051J Switch Local Intrfce... terminal Router( config)# interface ethernet 0/0 Router( config-if)# ip address Router( config-if)# no shutdown Configuring interface description Router# configure terminal Router( config)#... ADDRESSES Router# configure terminal Router( config)#interface type slot/port Router( config-if)#ip address Router( config-if)#no shutdown Configuring an Ethernet interface Router#