| Gather Clues | |
| A. | Ask Questions. i. What were you doing when the problem occurred? ii. Have there been any recent changes to the network? |
| B. | Have the customer recreate the problem while you watch. While watching, check for obvious user errors (ID10T errors), such as Caps-Lock being on. |
| Possible Solutions | |
| A. | Cable unplugged from NIC or switch/hub. Plug it in. |
| B. | Faulty cable. Test with cable tester or swap cables. |
| C. | Faulty or disabled NIC. Check if it is enabled in Windows and BIOS setup. Test with loopback. Swap with another NIC. |
| D. | Bad port or uplink port on switch/hub. Move the cable to a different port. |
| E. | Disabled port on managed switch. Login to switch and enable port. |
| F. | If Wireless, lost connection to access point. Make sure workstation is close enough to access point. Check for interference. Make sure wireless NIC is configured with correct SSID & passphrase. |