LPI Linux Certification in a Nutshell, 2nd Edition

Hardware Problems

One of the truisms of networking is that the majority of problems occur at the physical layer. Problems can include a failed NIC, a hub that has lost power, or bad cabling. A discussion of the relevant applications for troubleshooting physical networking issues follows.

Physical Connection Issues

Although the LPI Exam focuses mostly on local configuration issues that can be discovered and resolved by using applications such as ifconfig and hostname, it is important to understand that other devices may be causing problems.

Cabling

While relatively unusual, cables can become weakened and wires can sever. Some offices may have wiring that is routed beneath carpets that receive substantial traffic. Users may also be able to roll over the cables with their chairs. When it comes to troubleshooting such cabling problems, consider the following steps:

1. Obtain a working system and attach it to the cable in question. If the cable works, you know you have a problem with the Linux system.

2. Check for loose or broken cable connectors. If a connector is broken, the cable may be only partially inserted, causing failed or intermittent connections.

Failed networking devices

Hubs, switches, and routers are generally quite reliable, but it is possible that an intervening device, rather than the Linux system, has failed. One way to confirm your suspicion that a hub or switch has failed is to use a crossover cable and connect the affected system to another working system. A crossover ...