MIME / HTML / UUENCODE

Background information | Disabling | Email packages that don't support it | Disclaimer - Please Read

Many readers of the ATM mailing list use basic email packages that are capable of handling only text information. Many members subscribe to the digest version of the list. And finally, many users pay for access on a per-byte basis. For both of these reasons, you should not send MIME, HTML, or UUENCODED emails to the list.

Background information

What do these acronyms mean? MIME is the Multimedia Internet Mail Extensions, and is a specification that programmers use to enable mail interoperability. If your emailer supports MIME, you can send messages that contain formatted text (fonts, bolding, colors, etc.), attached files, and embedded objects (such as pictures) to other users even if they use a different email application. Of course, their emailer has to support MIME in order for them to receive your message properly.

HTML, the language of web pages, is frequently used by Internet-oriented mail packages to provide text formatting capabilities, without the other capabilities offered by MIME. In fact, the modern popular email packages that offer MIME encoding often use HTML to format the text and use the MIME standard for attached files, etc.

UUENCODING is a technique for convering binary files, such as pictures or executables, into plain text files that can be sent easily over the Internet (without something fancy like MIME). Using a UUENCODE program, you convert your binary file to text. Then, typically you would send that text as the body of your email or posting to USENET. The recipient of your note would use a similar program to decode your text information back to binary form. If you want to attach pictures to your emails, read this note.

So what's this got to do with the ATM list?

The problems for us on the list is that not all email packages support these standards. More importanty, the program that compiles the digests doesn't fully support these standards. When you send a note that contains information encoded with one of these techniques, the digest compiler just adds your note to the digest, complete with the encoded information. It does not first convert your submission to a human-readable form.

So, those of us receiving the digest version of the list, or those of us using older email applications, have to wade through lots of codes that were meant by their designers to be filtered out by our computers. If you would like to see an example of what we receive, click here.

Andy Steere, the archives administrator also notes that he must remove, by hand, any encoding information from emails he adds to the archives. This requires hours of his (volunteer) time each month.

How can you help prevent this problem?

Disabling MIME / HTML encoding

The Microsoft email programs (Outlook, Exchange, Internet Mail and News) and newer versions of Netscape are set by default to do MIME / HTML encoding of all messages. You can disable this setting by following the procedures detailed here.

Please note, changing this setting will affect all mail you send using your email program (except for Exchange).

For Netscape Navigator:

  1. Choose Options, Mail and News Preferences
  2. On the Composition tab, select Allow 8-bit (instead of Mime Compliant (Quoted Printable))
  3. Click on OK
For Netscape Communicator:
  1. Choose Preferences, Mail & Groups, Messages
  2. Deselect "By default, send HTML messages"
  3. Click on OK
For Microsoft's Outlook and Outlook Express:
  1. Choose Tools, Options
  2. On the Send tab in the Mail sending format section, choose Plain Text (instead of HTML)
  3. Click on OK
For Microsoft Exchange:
  1. Open address book
  2. Highlight the ATM list address (atm@atmlist.net)
  3. Right click and choose Properties
  4. Click on the Send Options button
  5. Disable MIME and HTML on the options page
  6. Click on OK
For Microsoft Internet Mail:
  1. Choose Options, Mail Sending Format
  2. Click on Settings to open Plain Text Settings with MIME Message Format dialog box
  3. Change Encode Text Using: "Quoted Printable" to "None"
  4. Click on OK
If you use a package that is not listed here and know the procedures for disabling MIME or HTML encoding (assuming it's the default), the please send that information to the FAQ Maintainer.

What email packages don't support MIME/HTML:

According to one person who responded to my original note, most email packages do support MIME but not HTML. This means that they can encode file attachments and send them (using MIME) but don't format or interpret messages encoded with HTML. Regardless, the digest engine does not interpret these message correctly. So, please disable this feature in your emailer.

Email application Supports MIME Supports HTML
Lotus Notes Yes Yes
versions >= 4.6
Microsoft Outlook Yes Yes
Microsoft Mail ? ?
Microsoft Internet Mail and News Yes Yes
Netscape Mail Yes Yes
Eudora Yes No
Pine Yes No
UNIX mailers Some No
Want to add your's to the list? Send information about your emailer to the FAQ Maintainer.

DISCLAIMER

This information is presented on a purely informational basis. Not all required information might be included: read the documentation that accompanies your software. You agree to accept any and all consequences of any actions you take based on the information contained in this document. You agree that the ATM FAQ Maintainer and any other members of the ATM list are not responsible for any damages, whether real or consequential, due to information included, or omitted, in this document.

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This document, its contents, and its Web representation are Copyright ©1996, Tim Poulsen. For complete copyright information, including allowed uses of this FAQ, please see Section 8. Initially created on Thursday, September 12, 1996 by Tim Poulsen, poulsen@netacc.net.