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Exchange 2010 Edge Transport Servers Removing Attachments with Long Names RRS feed

  • Question

  • Hi, 

    We are having an issue where attachments with long names are being removed from an email before being delivered.  We are using Exchange 2010 for relay and the Edge servers seem to be removing the attachments.  I can confirm the following;

    • Attachment filtering agent is enabled on the servers
    • The file type extension is .xlsx and is NOT included in the attachment filtering list so should not be getting matched
    • The software sending the emails is Microsoft's ATA and we have no control over attachment character length

    Hopefully someone can help me with this without the need of disabling the attachment filtering.

    Thanks!

    Wednesday, April 19, 2017 9:58 PM

All replies

  • Hi SonJim,

    I know you don't want to disable the attachment filtering agent, however, firstly I'd also recommend we disable it temporarily, to comfirm if the issue is caused by the agent.

    If disable the agent, the issue disappeared, then we can enable it again, and check the attchment filter entry settings:

    1. Check if there is any entry that filters e-mail attachments based on a file name, the attachment's long name may include some characters match it exactly.

    2. Also check the entry that filters attachments based on content type, these removed attachments may contain the MIME content type.

    Best Regards,


    Niko Cheng
    TechNet Community Support


    Please remember to mark the replies as answers.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.



    Thursday, April 20, 2017 3:01 AM
    Moderator
  • Hi Niko,

    Thanks for your response. The attachment name is something like the following excluding quotes;

    "Reconnaissance using directory services enumeration 58f7ac83c0ea2d0a8800495d.xlsx"

    The export of the attachment filter list is;

    FileName:*.ade
    FileName:*.adp
    FileName:*.app
    FileName:*.asx
    FileName:*.bas
    FileName:*.bat
    FileName:*.chm
    FileName:*.cmd
    FileName:*.com
    FileName:*.cpl
    FileName:*.crt
    FileName:*.csh
    FileName:*.exe
    FileName:*.fxp
    FileName:*.hlp
    FileName:*.hta
    FileName:*.inf
    FileName:*.ins
    FileName:*.isp
    FileName:*.js
    FileName:*.jse
    FileName:*.ksh
    FileName:*.lnk
    FileName:*.mda
    FileName:*.mdb
    FileName:*.mde
    FileName:*.mdt
    FileName:*.mdw
    FileName:*.mdz
    FileName:*.msc
    FileName:*.ps1
    FileName:*.ps1xml
    FileName:*.ps11
    FileName:*.ps11xml
    FileName:*.ps2
    FileName:*.ps2xml
    FileName:*.psc1
    FileName:*.psc2
    FileName:*.msi
    FileName:*.msp
    FileName:*.mst
    FileName:*.ops
    FileName:*.pcd
    FileName:*.pif
    FileName:*.prf
    FileName:*.prg
    FileName:*.reg
    FileName:*.scf
    FileName:*.scr
    FileName:*.sct
    FileName:*.shb
    FileName:*.shs
    FileName:*.url
    FileName:*.vb
    FileName:*.vbe
    FileName:*.vbs
    FileName:*.wsc
    FileName:*.wsf
    FileName:*.wsh
    FileName:*.xnk
    ContentType:application/hta
    ContentType:x-internet-signup
    ContentType:application/javascript
    ContentType:application/x-javascript
    ContentType:text/javascript
    ContentType:application/msaccess
    ContentType:application/prg
    ContentType:text/scriptlet
    ContentType:message/partial
    ContentType:application/x-msdownload

    I do not understand the concept of MIME so hopefully some of this gives a clue to which I should do, will turn it off if we don't get any answers from this just means I will need to go through our change request procedures.

    Thanks again


    Thursday, April 20, 2017 9:26 AM
  • Hi SonJim,

    Have you confirmed if the issue is caused by attachment filtering agent ?

    If had verified, we can remove the content type entries one by one to confirm which entry caused this issue:

    Remove-AttachmentFilterEntry -Identity ContentType:application/hta
    Best Regards,



    Niko Cheng
    TechNet Community Support


    Please remember to mark the replies as answers.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Tuesday, April 25, 2017 6:27 AM
    Moderator
  • Hi Niko,

    I am going to raise a change to get it turned off today - will then try generate some alerts to see if the attachment is stripped.

    Thanks for your help, will keep you up to date,

    SonJim

    Tuesday, April 25, 2017 7:57 AM
  • I believe this is the problem, haven't attempted fix yet but this must be it as it is exactly the same issue we are receiving:

    https://support.microsoft.com/en-gb/help/2855809/email-message-attachments-are-removed-incorrectly-on-an-exchange-server-2010-edge-transport-server

    Friday, May 19, 2017 12:08 PM