Cisco Systems CCNA 2 manual Troubleshooting IP addressing issues, LAB-C#show ip route

Show a routing table.

LAB-C#show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B – BGP, D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area, E1 - OSPF external type 1, E2 - OSPF external type 2, E – EGP, i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, *

-candidate default, U - per-user static route Gateway of last resort is not set

C 204.204.7.0/24 is directly connected, Serial0

C 223.8.151.0/24 is directly connected, Ethernet0

R201.100.11.0/24 [120/1] via 199.6.13.1, 00:00:06, Serial1 R 219.17.100.0/24 [120/1] via 199.6.13.1, 00:00:06, Serial1 R 192.5.5.0/24 [120/2] via 199.6.13.1, 00:00:06, Serial1

C 199.6.13.0/24 is directly connected, Serial1

R 205.7.5.0/24 [120/2] via 199.6.13.1, 00:00:06, Serial1

R 210.93.105.0/24 [120/1] via 204.204.7.2, 00:00:07, Serial0

4.2.6Troubleshooting IP addressing issues

Addressing issues are the most common problems that occur on IP networks. Three commands can be used to perform troubleshooting:

•telnet – verifies the application layer software between the source and the destination. This is the most complete test mechanism available.

•ping – uses the ICMP protocol to verify the hardware connection and the IP address of the network layer. This is a very basic test mechanism.

•traceroute – is used to find failures in the path from the source to destination. Traceroute uses time-to-live values to generate messages from each router along the path.

Troubleshooting is one of the most important skills of a network associate. The majority of time in the workplace will be spent troubleshooting. Students should develop these skills at every opportunity. Help students learn the logical process, what to look for, and the tools to use. Always use the OSI model to teach troubleshooting from Layer 1 to Layer 7. For students to become proficient at troubleshooting, it must be a normal part of the labs. Each lab should include a troubleshooting session. This could be a discussion about problems that might be experienced in the lab or problems can be placed on the student network.

49 - 238 CCNA 2: Routers and Routing Basics v3.1 Instructor Guide – Module 4 Copyright ♥ 2004, Cisco Systems, Inc.