Information Technology

Sending e-mail attachments

To reduce spam and thwart "phishing," Wittenberg and many other locations screen e-mail attachments.

Common do's and don'ts:

• DO close the document before trying to send it. It's easy to accidentally attach the open copy of the file, which makes the file look "incomplete" or broken to an e-mail scanner program. (Possible result - the attachment will be stripped from the e-mail.)


• DO keep the file attachment under 50 megabytes if sending to a Wittenberg e-mail address. For most places we're familiar with, 10 megabytes is the more common limit so if it is a large file you may want to check with the recipient first. (Possible result - bounced e-mail or attachment stripped from message.)


• DON'T use special characters in file names. This has always been true, but keep in mind that special characters also includes things like parentheses, quotation marks, and slashes. Hyphens, underlines, and spaces are fine. (Possible result of using special characters - bounced e-mail or attachment stripped from message.)


• DON'T use file names with more than one "." Example: e-mailupgrade.2007.09.05.docx will trigger a reaction from e-mail scanning programs. The reaction ranges from the program stripping the attachment from the message to outright blocking the e-mail message, depending on that location's administrative choices. A better name choice might be e-mailupgrade-2007-09-05.docx, where only the file extension is after the period.

General etiquette when it comes to sending file attachments

• Large files: how can you define "large"? Many (if not all) e-mail account administrators enforce some limit to the size of attachments accepted. For many, it's around 10 megabytes. Even if the e-mail server will accept a file larger than that, is it a good idea to send large files?
  • Options to consider before sending large files include:
    • Check with the recipient first to see if they have room in their e-mail account for the attachment or if there are limits imposed by the site.
    • If you're sending the attachment to many people (campus wide for instance), could you post the file on a web page or other shared resource instead? Sending a link to a file always results in a smaller e-mail message than including the attachment.
    • Could you save the file differently to make the attachment smaller? One example might be to save a .bmp image as a .jpg file instead, saving up to 3/4 of the attachment size.
    • Are you sure it's going to a Witt e-mail address? Many students forward their e-mail to another account, enabling them to check e-mail from a single location. If the e-mail is forwarded to another address, Witt's attachment limits don't apply-the limits as the recipient location do.
• File types-keep it usual.
  • So what's usual? Documents such as pdf, zip, Microsoft Office documents and presentations, etc. are "usual". If you need to send something else, check with the recipient to be sure that the file type is accepted and that the person has a program to open the file once it arrives.

This document last reviewed April 26, 2013.