TFTP Error: Access Violation

Article:TECH108143  |  Created: 2002-01-18  |  Updated: 2007-01-19  |  Article URL
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Technical Solution


During early client boot you receive an access violation trying to download the Boot.ovl file


The boot agent tries to load a boot file from an inappropriate location or with insufficient access rights. If on your CCM client computer you get a file access error or "file not found" error, then proceed according to the following steps.

To troubleshoot the problem
  1. Determine which DHCP or Bootp server answered your client computer's request.
    Usually this server's IP address is displayed on the client's screen. If you can't find this information on the screen, then you must use a network sniffer.
  2. Check the bootfile option set on this DHCP/Bootp server, and find out whether Boot.ovl exists in this location and whether it is world-readable.
    • For BOOTP servers, check the file for a missing bootfile or bootpath entry.
    • For DHCP servers, check the syntax of the bootfile option. the default syntax must be in UNIX format and contain the absolute path to the Boot.ovl file. Do not use drive letters.

      The default path is /etc/integra/tftp/boot.ovl and must be the same as described in the image path in the following registry key:

      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\CCM tftp
  3. Check whether the bootfile option was sent to your CCM client computer. Some Bootproms write the file name on the screen. If you can't find this information on the screen, you must use a network sniffer.
  4. Try to download Boot.ovl using the command-line tftp program on the host where your tftp server is running (Tftp.exe).
    • Double check the bootfile name. It must be an absolute path in which the drive letter is omitted.
    • Is the tftp server running?
    • Look for errors in the log files of your tftp server.
    • Is the UDP port 69 active?
  5. If the Boot.ovl file can be downloaded using the command-line tool, then run the command-line tool from the same network segment on which your CCM client computer resides.
    • If the download works, then your CCM client computer is requesting the wrong file.
    • If the download fails, then UDP port 69 may be blocked by your router.

If you require technical assistance, please provide a network trace of the boot procedure.

For more information, read How to install the CCM TFTP Server manually.

Technical Information
NT DHCP servers : If you recently added a new DHCP option redeploy at least SP 5. Some options are not properly transmitted on NT unless SP 5 is used.

Additional DHCP option 13: Bootfile Size set to 1: Certain types of DHCP servers may supply boot file names that are not terminated in a null character. Intel Architecture Labs PXE 2.1 addresses the null terminated boot file names, but fails to work correctly if the DHCP boot file size option is not present when using Intel Boot Agent 4.0.19.

This issue has been corrected in Intel Boot Agent 4.0.22. Customers using IBA 4.0.19 and running into this issue can also work around it by setting DHCP boot file size tag 13 as a non-zero value (ideally the size of the boot file).

If you are working with the CCM Relocator 5.0: ON Technology confirmed a problem with the early relocator design where the checksum of the data segment was inappropriate, causing a tftp error. This was fixed in the subsequent relocator builds. Use at least the build provided with 5.01.

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