Crest

UBC Mathematics: Why your Email was rejected.


Banned attachments

Your Email has a attachment with a banned extension:

Attachment: bad.exe
Extension: .exe

Our mail server rejects Email with attachments that have the following characteristics:

  • Ends in extensions:
    .ade .adp .bas .bat .chm .cmd .com .cpl .crt .exe .hlp .hta
    .inf .ins .isp .js .jse .lnk .mdb .mde .msc .msi .msp .mst
    .pcd .pif .reg .scr .sct .shb .shs .url .vb .vbe .vbs
    .wsc .wsf .wsh
    CLSID (e.g. file.jpg.{12345-1235-abe8-hwhwh}) extension
  • Archives extensions:
    .rar .zi .zip
  • Filenames:
    winmail.dat
  • File types:
    Single/double/triple Base64 encoded Windows executable signature.

The following URLs are references on why certain attachments should be rejected:

http://support.microsoft.com/support/kb/articles/Q262/6/17.ASP
http://www.nsa.gov/snac/support/C43-017R-2003.pdf
http://www.advosys.ca/papers/mail-policies.html

Most Emails that we reject based on these policies (> 99%) are viruses.

Here are some strategies to cope if you are sending something useful:

  • First of all, ask yourself if it is really necessary to transfer this file type? Many Email users can either refer to an official site to download executables, or offer a suitable channel for distribution without resorting to attaching it to an Email.
  • You can use another file type (e.g. use compressed tar instead of zip).
  • You can also transfer it by some other method, such as
    • posting it on a website.
    • putting it in on a anonymous FTP archive.
    • Inlining the data into the body of your Email (e.g. .url)
  • Rename the attachment. For example, "data.zip" can be renamed to "data.zzz", then sent with an explanatory note.

Remedial Actions

Here are some steps you can take if your Email cannot be delivered. It is helpful when reporting problems to include the error messages you received from our mail server as to the reason why your Email was rejected: it greatly speeds up the resolution of your problem.

  • Contact the IT staff using the
    MathNet User Services: IT Submission Form

    Don't forget to leave contact information in case we have to get back to you.

  • Email to this address:
    falsepositive(at)math(dot)ubc(dot)ca

    This address is exempt from most forms of filtering, but you must direct your complaint solely to this address, or the exemption may not apply. Also, it won't work if your entire network is being blocked; use the other methods instead.

  • Contact the IT staff by phone or in person:
    UBC Mathematics IT Support Staff
    Office: MATH222B
    Phone: 604-822-6621
  • Send your Email using another Email address or from another network.