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Archived - Mac OS X can't connect via Comcast Internet service provider

If you have a Comcast cable modem, you might not be able to connect to the Internet. This issue may be intermittent.
This article has been archived and is no longer updated by Apple.
When this happens, the computer does not receive a DHCP lease with a valid IP address from Comcast. Instead, it uses a self-assigned 169.254.x.x address, and cannot access the Internet.

This can happen with Mac OS X 10.2 to 10.3.9 when your connection is configured via DHCP. This is not known to affect PPPoE accounts.

For Mac OS X 10.3

To resolve the issue, try updating to Mac OS X 10.3.5, which you can get here.

If the issue persists after updating, contact Comcast for further assistance. They may need to reset some equipment, specifically the cable modem termination system (CMTS).

For Mac OS X 10.2

Change your computer's configuration using these steps:

  1. From the Go menu in the Finder, choose Go to Folder.
  2. In the Go To Folder dialog, type this path:

    /System/Library/SystemConfiguration/IPConfiguration.bundle

  3. In the resulting window, select the Resources folder.
  4. From the File menu, choose Get Info.
  5. Click the disclosure triangle next to Ownership & Permissions.
  6. Look at the lock icon. If it's closed, click it to open it. If prompted to authenticate, enter your user password. (You must be logged in as an administrator, or "admin" user.)
  7. Change the Owner from "system" to the name of the user account that you're logged in with.
  8. Close the Resources Info window.
  9. Open the Resources folder, and select the file named IPConfiguration.xml
  10. From the File menu, choose Get Info.
  11. Click the disclosure triangle next to Ownership & Permissions.
  12. Change the Owner from "system" to the name of the user account that you're logged in with.
  13. Close the IPConfiguration.xml Info window.
  14. Be sure that IPConfiguration.xml is still selected in the Finder, then go to the File menu and choose Duplicate.
  15. Rename the duplicate "IPConfiguration copy.xml" to "IPConfiguration.xml.orig".
  16. Go back to "IPConfiguration.xml", and open it in TextEdit.
  17. From the Edit menu, choose Find.
  18. In the Find window, in the Find field, type: InitialRetryTimeSeconds
  19. Click the Next button.
  20. You should find a section that appears as follows:

        <key>InitialRetryTimeSeconds</key>
        <integer>1</integer>
    

  21. Change <integer>1</integer> to <integer>8</integer>.
  22. The section should now appear as follows:

        <key>InitialRetryTimeSeconds</key>
        <integer>8</integer>
    

  23. In the Find window, in the Find field enter: MaximumRetryTimeSeconds
  24. Click the Next button.
  25. You should find a section that appears as follows:

        <key>MaximumRetryTimeSeconds</key>
        <integer>8</integer>
    

  26. Change <integer>8</integer> to <integer>12</integer>.
  27. The section should now appear as follows:

        <key>MaximumRetryTimeSeconds</key>
        <integer>12</integer>
    

  28. Save the changes to the IPConfiguration.xml file, and quit TextEdit.
  29. In the Finder, select IPConfiguration.xml.
  30. From the File menu, choose Get Info.
  31. Click the disclosure triangle next to Ownership & Permissions.
  32. Change the Owner from the name of the current user to "system".
  33. Close the IPConfiguration.xml Info window.
  34. Close the Resources window.
  35. Select the Resources folder.
  36. From the File menu, choose Get Info.
  37. Click the disclosure triangle next to Ownership & Permissions.
  38. Change the Owner from the name of the current user to "system".
  39. Close the Resources Info window.
  40. Restart the computer.

If the issue persists after performing the above steps, contact Comcast for further assistance.

Last Modified: Feb 17, 2012
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  • Last Modified: Feb 17, 2012
  • Article: TA21545
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