Table 9-6 Troubleshooting Tools for Wired and Wireless Networks
| Tool | How Used |
| Cable tester | Tests network cables for proper wiring and operation |
| Loopback plug | Tests network port or cable connected to network port |
| Punch-down tool | Attaches TP cables to an RJ-45 jack |
| Toner probe (also known as tone | Tests individual wire pair; more widely used with |
| and probe) | phone lines than network cables |
| Wire stripper | Removes outer jacket from TP cables |
| Crimper (also known as “crimping | Attaches RJ-11 or RJ-45 plug to paired TP cables; |
| tool”) | different crimping dies are needed for RJ-11 and |
| RJ-45 plugs | |
| Ping* | Tests connectivity with another host on your network |
| or a remote IP address or website | |
| IPConfig* | Displays IP address, subnet mask, gateway, DNS |
| servers, releases and renews IP address, depending | |
| upon options used with program | |
| Tracert* | Traces route from your system to the specified IP |
| address or website; checks up to 30 hops by default | |
| Netstat* | Displays TCP connections in use; can also display |
| UDP connections and Ethernet stats, depending upon | |
| selected options | |
| Nbtstat* | Displays services running on your computer or a |
| remote computer | |
| Net* | Displays and uses network resources |
| Wireless locator | Detects wireless networks |
*Windows command-line program; open command prompt to use this program
Use Table 9-7 to look up typical symptoms, problems, and solutions for wired and wireless net-work issues.
| Chapter 9: Troubleshooting 183 | |||
| Table 9-7 Network Symptoms, Problems, and Solutions | |||
| Symptom | Possible | Items to Check | Typical Solution |
| Cause | |||
| No connectivity | Wireless: Not | Check the wireless | Turn on the wireless network |
| connected to | connection. | adapter (laptop) or remove/ | |
| network. | reinstall the adapter with | ||
| Device Manager (laptop/ | |||
| desktop). | |||
| Open the wireless connection | |||
| manager and provide creden- | |||
| tials as requested to connect. | |||
| Wired: | Check the Ethernet | Replace the cable if defective. | |
| Disconnected or | cable. | ||
| defective net- | |||
| work cable. | |||
| No valid IP | Check the IP | Run IPConfig to check IP | |
| address. | address. | address. If IP address shows | |
| as 0.0.0.0, use IPConfig / | |||
| releaseandIPConfig /renew | |||
| to get new address from the | |||
| DHCP server. | |||
| If you cannot renew the IP | |||
| address, reset the router. | |||
| Router may be | Check the router. | Reset the Internet access | |
| out of service. | device, and then reset the | ||
| router. | |||
| APIPA address | Can’t connect to | Check router. | Reset the Internet access |
| DHCP server. | device, and then reset the | ||
| router. | |||
| Limited con- | DNS server | Check the DNS | If the DNS server has the |
| nectivity | may be out of | server in use with | same address as the gateway, |
| service. | IPConfig. | reset the Internet access | |
| device, and then the reset | |||
| router. | |||
| Local connec- | Router may be | Check the IP | If the device has IP address in |
| tivity | out of service. | address with | 169.254.x.x range, local con- |
| IPConfig. | nectivity only is possible. |
Reset the Internet access device, then reset the router.
184 CompTIA A+ Quick Reference
Table 9-7 Continued
