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Ethernet Troubleshooting Tips

If you are having trouble getting your Ethernet connection to work, here are some tips on diagnosing the problem. Contact the OIT Help Desk (545-9400, option 1) if these suggestions do not resolve your problem.

On this page:
Swap Ethernet Cables
Swap Ethernet Jacks
Verify IP Address
Disable Network Bridging (or Internet Connection Sharing)
Clear Browser's History & Temp Files

Swap Ethernet Cables

  1. Borrow an Ethernet cable that you know is working. Unplug your Ethernet cable from your computer and from your Ethernet jack.
  2. Using the new cable, connect your computer to the Ethernet jack.
  3. Turn on your computer and start up an Internet browser. If you can get online, you need a new Ethernet cable.
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Swap Ethernet Jacks

  1. If there is another active Ethernet jack within reach of your computer, unplug your Ethernet cable from your wall jack.
  2. Plug your Ethernet cable into the new jack.
  3. Turn on your computer and start up an Internet browser. If you can get online, there is most likely a problem with your Ethernet jack. Call the Help Desk (545-9400, option 1).
  4. If you cannot get online, it is most likely a configuration issue with your computer. Try the other troubleshooting tips.
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Verify IP Address

For All Windows Operating Systems

  1. Click Start, then Run.
  2. Type cmd, and click OK.
  3. At the command prompt, type ipconfig /all and hit Enter.
  4. Note the IP address. If it is anything besides a 128.*.*.* address, continue to the next step.
  5. At the prompt, type ipconfig /release, hit Enter, and then type ipconfig /renew and hit Enter.
  6. Type ipconfig /all once more: if the IP address is still not a 128.*.*.* address, call the OIT Help Desk (545-9400, option 1).

For Macintosh OS 10.x

  1. From the Apple Menu (upper left corner of the Mac desktop), select System Preferences.
  2. Under Internet & Network, click Network.
  3. On the TCP/IP tab, choose Built-in Ethernet from the Show drop-down menu.
  4. The IP address will be displayed. If it is anything other than a 128.*.*.* address, continue to the next step.
  5. Unplug the Ethernet cable from your computer. Wait until the IP address clears.
  6. Plug the cable back into your computer. If the new IP address begins with 128.119.*.*, you should be all set. If it is anything other than a 128.*.*.* address, continue to the next step.
  7. From the Configure drop-down menu, select Manually. Enter the IP address 192.168.0.1 and subnet mask 255.255.255.0. Click Apply Now.
  8. From the Configure drop-down menu, select Using DHCP server. Click Apply now.

For Macintosh OS 9.x

  1. From the Apple Menu (upper left corner of the Mac desktop), select Control Panels > TCP/IP.
  2. The Connect via field should be set to Built-In Ethernet. The IP address will be displayed. If it is anything other than a 128.*.*.* address, continue to the next step.
  3. From the Edit menu, select User Mode.
  4. Change User Mode to Advanced. Click OK.
  5. Click Options. Switch to Inactive. Click OK.
  6. Close the TCP/IP control panel, saving changes.
  7. After two minutes, reopen the TCP/IP control panel. Click Yes.
  8. Click Options. Uncheck Load only when needed. Click OK.
  9. Close the TCP/IP control panel, saving changes.
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Disable Network Bridging (or Internet Connection Sharing)

Ethernet jacks on campus will automatically shut off once they detect simultaneous connections to the campus network.

  1. Use only one network connection at a time. Disable your wireless connection when using Ethernet.
  2. Your computer may be configured to bridge wired and wireless connections simultaneously. Disable network bridging (or Internet Connection Sharing).

Learn more about how to disable multiple network connections and turn off network bridging.

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Clear Browser's History & Temp Files

Make sure you are using Netscape Navigator 4.79 or higher, or Internet Explorer 5.5 or higher.

Internet Explorer 5.x or 6.x

  1. Select Tools > Internet Options.
  2. On the General tab, under Temporary Internet Files, click Delete Files ... Under History, click Clear History.

Netscape Navigator 7.0

  1. Select Edit > Preferences.
  2. Click Navigator, then click History. Click Clear History on the right-hand side.
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Need Help?

If you encounter problems, submit an online Help Request.
- or -
Contact the OIT Help Desk at 545-9400.

Last revised March 02, 2004