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WDS and DHCP trouble

    Question

  • Hello!

    I have set up a WDS on a server 2008 R2 and under install images i have one and under boot images there is one. Then i have manually used a tftp client to access these files and "boot\x86\wdsnbp.com" all of them i can download successfully from a subnet.

    So i think that my WDS is configured correctly, however i am having trouble with our DHCP. we have a non windows DHCP and through it i can successfully get an address when i boot on the network. But after that it just gives me PXE-M0F exiting boot agent.

    I have set the dhcp option 66 and 67 to boot\x86\wdsnbp.com and the ip address of the WDS, and the correct bootp settings. However, they do not seem to bite. So i am wondering if there is a way to query the DHCP for all of the information it distributes when a client tries to pxeboot. The goal is to be able and see if i have made faulty configuration on the DHCP.

    I am also considering using IP Helpers instead, We have a non windows DHCP DNS server, a cisco router and a WDS. What would i need to configure on the router to not interfere with any other DHCP operations?

    Monday, August 27, 2012 7:58 AM

Answers

  • it seems that "\x86" has been replaced with "\206" in the bootfile response.
    this might be your DHCP server, treating "\x8" as an escaped string
    i've seen it somewhere, that some servers need to double escape backslash strings, maybe you need that.
    e.g. set the bootfile option to be \\boot\\x86\\wdsnbp.com

    Don
    (Please take a moment to "Vote as Helpful" and/or "Mark as Answer", where applicable. This helps the community, keeps the forums tidy, and recognises useful contributions. Thanks!)


    • Edited by DonPick Monday, August 27, 2012 10:49 AM
    • Marked as answer by Plindgren Monday, August 27, 2012 11:18 AM
    Monday, August 27, 2012 10:46 AM

All replies

  • I ran wireshark on the WDS Server and it turns out the client does get the IP of the WDS. But the TFTP tra fails:

    From WDS to PXEclient
    
    Trivial File Transfer Protocol
    [source file: boot\206\wdsnbp.com]
    Opcode: Error Code (5)
    Error Code:Illegal TFTP Operation (4)
    Error message: Access violation

    What does this indicate?

    As stated before, when i manually use a TFTP client on my domain joined Win 7 to transfer files from the WDS to the client locally it works with no errors.

    Monday, August 27, 2012 10:33 AM
  • Hi,

    you can use wireshark or MS Netmon to capture a trace of the DHCP discover/offer/request/ack sequence.
    Since you seem to be having trouble with the "offer" part of things, this should be enough.

    Some further information (courtesy Symantec) about what you should be seeing, and some background, is here.
    Also, how to setup a Cisco router for the "ip helper-address".
    You can setup multiple ip helper-addresses, so that the dhcp discover is sent to both your dhcp-server and also your WDS (at the same time).
    This is a commonly preferred solution (preferred over option 66/67, since 66/67 is not always respected by all components)

    http://www.cisco.com/en/US/docs/switches/lan/catalyst2350/software/12.2_46_ey/configuration/guide/swdhcp82.html

    http://www.intel.com/support/network/sb/cs-028533.htm

    http://www.symantec.com/business/support/index?page=content&id=HOWTO8573

    http://www.symantec.com/business/support/index?page=content&id=HOWTO8616


    Don
    (Please take a moment to "Vote as Helpful" and/or "Mark as Answer", where applicable. This helps the community, keeps the forums tidy, and recognises useful contributions. Thanks!)


    • Edited by DonPick Monday, August 27, 2012 10:37 AM
    Monday, August 27, 2012 10:36 AM
  • it seems that "\x86" has been replaced with "\206" in the bootfile response.
    this might be your DHCP server, treating "\x8" as an escaped string
    i've seen it somewhere, that some servers need to double escape backslash strings, maybe you need that.
    e.g. set the bootfile option to be \\boot\\x86\\wdsnbp.com

    Don
    (Please take a moment to "Vote as Helpful" and/or "Mark as Answer", where applicable. This helps the community, keeps the forums tidy, and recognises useful contributions. Thanks!)


    • Edited by DonPick Monday, August 27, 2012 10:49 AM
    • Marked as answer by Plindgren Monday, August 27, 2012 11:18 AM
    Monday, August 27, 2012 10:46 AM
  • Thanks, i would have never figured out the double backslashes.
    Monday, August 27, 2012 11:19 AM
  • Hi,

    Glad to know the issue got fixed.

    Towards the WDS and DHCP, it's really need to clarify the issue such as third party DHCP server or WDS/DHCP in different subnet.

    There are some known issues when deploying WDS with DHCP, there is a link for your reference:

    Title: Known issues with configuring Windows Deployment Services

    URL: http://technet.microsoft.com/en-us/library/cc771670(v=ws.10).aspx

    I hope it will help you to have a better understanding about WDS.

    Regards,

    James


    James Xiong

    TechNet Community Support

    Wednesday, August 29, 2012 1:23 AM
    Moderator