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How to Troubleshoot Error 678 for High Speed Internet

Error 678 is returned by Windows to indicate that the connection attempt failed. Despite what the error description implies (remote computer failed to respond), the connectivity issue may be caused by a hardware or software misconfiguration on your computer, or by a line related issue (static, excess humidity, etc.).


Troubleshoot Error 678

The information provided here can help you troubleshoot error 678 if you are working on a stand-alone (non-networked) computer. If a router is connected to the High Speed Internet modem, disconnect the router and connect the modem directly to the computer. If you do not have High Speed Internet software installed and are using a router, install the High Speed Internet software. Once that is done, you can attempt connection. If the connection is successful, then the issue was router related. If the connection attempt fails, follow these instructions.

For Windows XP:
  1. Ensure that your scheduled High Speed Internet installation date has already passed.
  2. Ensure the modem is turned on.  How can I power cycle my DSL modem?   Once modem is turned on, cold boot the PC.
    • If the power light is unlit, verify that the power cord is plugged in securely and that power is supplied.
    • If the sync light does not turn solid green in approximately one minute, the modem is not establishing a DSL connection. Try the following:
      1. Check the phone cord between modem and wall jack.
      2. Ensure filters are installed at proper locations. How do I install line filters?
      3. Check for Electro-Magnetic Interference.
    • Make sure both the Ethernet link light and the link light on the Network Interface Card (NIC) are either solid or blinking (not off). If they're not, then follow the steps below:
      1. Make sure the Ethernet cable is a straight-through cable (like the one supplied by AT&TIS).
      2. Swap the Ethernet cable end-for-end.
      3. If the link lights remain off and you have another Ethernet cable to use, substitute the cable and see if the lights come on.
      4. If the light still remains off, the NIC and/or modem may be at fault. 

      Try to connect again and see if you still experience error 678. If you still receive that error, continue to step 3.
  3. Click on Start > Control Panel.
  4. Double-click on Network Connections.
  5. Make sure the NIC appears in the Network Connections Window as a local area connection and is enabled. Ensure that TCP/IP is bound to the device. Excess protocols such as IPX/SPX, NETBEUI, Internet Connection Sharing (ICS), and Virtual Private Networking (VPN) may cause connection problems. You may also try clicking on the appropriate local area connection and selecting Repair.
  6. In the Network Connections window, select the broadband connection and then click Change settings of this connection in the left menu.
  7. Click on the Options tab.
  8. Ensure that the Display Progress while connected box is selected.
  9. Ensure that the Prompt for Name and Password, Certificate, etc. box is selected.
  10. Ensure that the Redial if line dropped box is selected.
  11. Click on the Security tab.
  12. Ensure that the Typical box (recommended settings) is selected.
  13. Ensure that the Allow unsecured password box is selected.
  14. Click on the Networking tab.
  15. In the Type of Broadband Connection to Make dialog box, select Point to Point Protocol over Ethernet (PPPoE).
  16. In the This Connection Uses the Following Items dialog box, ensure Internet Protocol (TCP/IP) is selected.
  17. Highlight Internet Protocol (TCP/IP) and click on the Properties button.
  18. Ensure that the Obtain an IP Address Automatically box is checked. In addition, the Obtain DNS Server Automatically box should be checked.
  19. Try to make a connection. If the connection is not established, then follow these steps:
    1. Go to Start > Control Panel.
    2. Double-click on the icon labeled Network Connections.
    3. Delete the broadband connection icon. If there is a shortcut to the connection on the desktop, delete that as well.
    4. Recreate the broadband connection by double-clicking on Make a New Connection.
  20. Retry the connection . If you are still having a problem establishing a connection, go to the next step.
  21. Go to Start > Control Panel > Network Connections.
  22. Select the LAN connection associated with the NIC and select Change settings of this connection from the left menu.
  23. Ensure Client for Microsoft Networks and Internet Protocol (TCP/IP) are selected.
  24. Go to the Advanced tab and uncheck the Internet Connection Firewall.
    (Note: This is for troubleshooting purposes only. After the issue is resolved, you may want to reconfigure your firewall.)
  25. Make sure there is only one Broadband connection for High Speed Internet.
  26. Click the broadband connection and select Change settings of this connection from the left menu.
  27. Click on the Networking tab.
  28. Enable Client for Microsoft Networks and Internet Protocol TCP/IP only.
  29. Go to the Advanced tab.
  30. Disable Internet Connection Firewall and Internet Connection Sharing.
    (Note: This is for troubleshooting purposes only. After the issue is resolved, you may want to reconfigure your firewall.)
  31. Retry the connection