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AnswerProblem with malware inspection and large video files.

  • Wednesday, July 01, 2009 7:26 AMHallis Users MedalsUsers MedalsUsers MedalsUsers MedalsUsers Medals
     
    I'm using Beta 3 and have trouble downloading large video files when malware inspection is enabled. I have tried to uncheck the "Block files larger than 1000 MB" option, but it is still unstable. Specifically I try to download using the download manager ReGet. That does not work at all. If I open the file directly in Windows Media Player it works sometimes. If I disable malware inspection everything works as expected.

    For this test I am trying to download the following Channel 9 video: http://mschnlnine.vo.llnwd.net/d1/ch9/3/1/7/5/7/4/ThisWeekC9June26_2MB_ch9.wmv

    Is there a way to disable malware inspection for large files or spesific file types?
    Hallis

Answers

  • Saturday, July 11, 2009 5:55 PMBala Natarajan MSFT Users MedalsUsers MedalsUsers MedalsUsers MedalsUsers Medals
     Answer

    The size of the file is ~1GB so definitely adjusting or disabling the size is required. 

    The content type returned by the server is video/x-ms-wmv which is included in the fast trickling types. However, buffering and scanning have some overhead which may be noticeable, especially with slow download from the server. For example, if the download rate is exactly sufficient for playback (without EMP) adding accumulation and scanning will degrade it so that the player will need to pause the playback sometimes for buffering.

     

    As for asusing a download manager – EMP removes the range headers to force downloading full files to make sure we dont by pass malware inspection .
    Bala Natarajan [MSFT]| Sr. Support Escalation Engineer | CSS Security -TMG Beta support team | Email: bala.natarajan@microsoft.com | Office 425.704.4626 Bing it on bing.com

All Replies

  • Wednesday, July 01, 2009 5:33 PMBala Natarajan MSFT Users MedalsUsers MedalsUsers MedalsUsers MedalsUsers Medals
     
    i will test it in my lab and get back
    Bala Natarajan [MSFT]| Sr. Support Escalation Engineer | CSS Security -TMG Beta support team | Email: bala.natarajan@microsoft.com | Office 425.704.4626 Bing it on bing.com
  • Saturday, July 11, 2009 5:55 PMBala Natarajan MSFT Users MedalsUsers MedalsUsers MedalsUsers MedalsUsers Medals
     Answer

    The size of the file is ~1GB so definitely adjusting or disabling the size is required. 

    The content type returned by the server is video/x-ms-wmv which is included in the fast trickling types. However, buffering and scanning have some overhead which may be noticeable, especially with slow download from the server. For example, if the download rate is exactly sufficient for playback (without EMP) adding accumulation and scanning will degrade it so that the player will need to pause the playback sometimes for buffering.

     

    As for asusing a download manager – EMP removes the range headers to force downloading full files to make sure we dont by pass malware inspection .
    Bala Natarajan [MSFT]| Sr. Support Escalation Engineer | CSS Security -TMG Beta support team | Email: bala.natarajan@microsoft.com | Office 425.704.4626 Bing it on bing.com