RFC 1844

Multimedia E-mail (MIME) User Agent checklist 🎀

Part 1 of 2 💖

Okay bestie, this is RFC 1844 🦋 From the title block: it's from the Network Working Group 🌸, written by E. Huizer of SURFnet bv 💅, dated August 1995 ✨, and filed under the category Informational 📚. It also obsoletes RFC 1820 🔥 and that's all the header says on that front.

Status of this Memo ✨

Okay so this memo is giving info to the Internet community 💁‍♀️. It does not specify an Internet standard of any kind, so no pressure. Distribution of this memo is unlimited 🌍.

Abstract 🌈

The tea is that this doc hands you a checklist to make evaluating MIME capable User Agents way easier 💅. It also describes how to get access to a MIME test-responder, which generates test-messages 📨.

Introduction 🧚

So this checklist helps you evaluate MIME capable E-mail User Agents 💖. Important bestie: it is by no means a conformance or interoperability checklist 🙈. Those are strictly defined, measurable quantities, and this is not that. It's an interworking checklist instead, with a practical perspective, made for users and system managers 🫶.

Usage and submission 💌

If you run this checklist against a specific product 🎯, whether you're a vendor, an implementor or a user, you can submit the result to mime-check@nic.surfnet.nl. Make sure the subject reflects the name and version of the product 🏷️. This is an automated mailhandler, so PLEASE only submit filled-in checklists (in content-type text/plain or text/html) to that address 🙏. The info is made available at no cost so other people can browse through it at http://www.nic.surfnet.nl/surfnet/projects/surf-ace/mime/ 🌸.

SURFnet will attempt to verify the correctness of each submission, but all submitted info is made available as is, with no guarantees 🫠. SURFnet does not take any responsibility for errors in the data that's available, or for any damages from using that data 🙅‍♀️. Users who want to procure a UA are advised to use the data as an orientation and to run their own procurement tests, possibly using the checklist below as a guideline 📋. Also, vendors and implementors are encouraged to use the checklist results to level up their products 📈.

Getting test messages 📬

Some of the tests in the checklist need a test message, so here's how to grab one. Send mail to mime-test@relay.surfnet.nl with a subject field containing ONE of the following 👇:

text/plain
text/enriched
image/gif
image/jpeg
audio/basic
video/mpeg
application/octet-stream
application/postscript
message/rfc822
message/partial
message/external
multipart/mixed
multipart/parallel
multipart/digest
multipart/alternative
multipart/appledouble
application/wordperfect5.1
application/msword
application/rtf
X-local      <to test how your UA deals with undefined content-types>
nested    <returns a message that contains nested multipart contents>
iso-8859-1    <returns a message with text/plain; charset=iso-8859-1>

A message containing the requested content-type will be returned to the address in the from field 💖.

Checklist for Mime UAs 💅

okay bestie, heads up!! 🎀 Some items have multiple choice options, so more than one option can apply to the same item 💖

1. General information 🌸

1.1 Name and version of the product ✨

1.2 Name and addressing info of the manufacturer 🧚

1.3 What platforms are supported? Operating system, GUI and hardware requirements (if applicable), and which APIs are supported, like MAPI etc. 🦋

Note: Please use separate checklist forms for different platforms!! 🙈

1.4 What platform did you use for this checklist? Operating system, GUI and hardware 🫶

Note: Only one platform per checklist!! 💀

1.5 Is the software available in source format, binary format, or both? 💜

1.6 Pricing info. Is the software available:

• In the Public Domain, free of charge 🌈
• As shareware (what is the price?) 💸
• PD for non-profit use, but not for commercial use 🍓
• Commercially 👑

2. System installation, configuration and management 🦋

2.1 How complex or easy are installation and configuration? Are there any pitfalls that need attention? Can you configure per set of users (like a system-wide or LAN-wide default configuration) and/or per user? 🔥

2.2 Are there facilities for logging and/or accounting? 📝

2.3 Does the UA generate correct RFC-822 headers for outgoing messages? ✨

• From:, (and if necessary) Sender:
• Date:
• Message-id:

2.4 Can a non-privileged user change the "from" and/or "sender" field? 🙈

2.5 Does the UA have any size restrictions, either default or applied by the system manager, for:

• Message size
• Number of messages
• Number of folders
• Number of messages per folder

2.6 How secure is the user's mailbox when using this UA? Can other non-privileged users access the mailbox? 😭

2.7 What's the performance of the UA on this platform? This is hard to measure, so just give your subjective impression: slow, reasonable or fast. Think about things like:

• Displaying a text message
• Displaying a MIME message that contains an image
• Complex actions like sorting etc.

3. General UA properties 💜

3.1 Does the UA have a graphical interface, a character based interface, or both? 🎀

3.2 Does the UA support native RFC-822/MIME, or does it need a gateway? 🌸

3.3 Which protocols are supported for message delivery?

• a. SMTP (MX records or static routing to Mailhost)
• b. ESMTP
• c. POP (which version)
• d. IMAP
• e. Co-location with a specific MTA (which MTA)
• f. Other ...............

3.4 Which protocols are supported for message submission?

• a. SMTP
• b. ESMTP
• c. Co-location with a specific MTA (which MTA)
• d. Other ...............

3.5 Does the UA support these basic functionalities? 🧚

• List messages
• Read messages
• Delete messages
• Compose new messages
• Reply to messages (including the original message text in the reply, replying to the originator or to any or all recipients, etc.)
• Forward message
  • using MIME
  • using RFC-934 encapsulation, meaning the message is wrapped between ------- Forwarded Message and ------- End of Forwarded Message
  • Other .......
• Distribute message (the From: field does not change)

3.6 Does the UA support these header fields, and can the user supply them? 💅

       Generated correctly        Can be supplied by user
       - To:
       - Cc:
       - Bcc:
       - From:
       - Reply-to:
       - Subject:
       - Comments:

3.7 Does the UA support filing mail into folders? Are there any restrictions? 📂

3.8 Does the UA have a filtering mechanism that lets the user set up automatic processing of incoming mail (for example, automatically filing into specific folders)? If so, how simple is it to configure these filters? 🦋

3.9 Does the UA have a sorting mechanism that lets the user sort mail by date, subject, from field, etc.? If so, describe the possibilities and restrictions. 🔥

3.10 Does the UA support address lists and/or directory services?

• Local (local address list, local aliases, local distribution lists etc.)
• Whois++
• Ph (to CCSO server)
• LDAP or SOLO or other access protocols to a directory service
• Other .....

3.11 What other non-multimedia facilities does the UA support? ✨

3.12 What secure mail protocols does the UA support (in-line)? 🔐

• PEM (Privacy Enhanced Mail)
• PGP (Pretty Good Privacy)
• Other.....

4. MIME support 🌈

4.1 Does the UA support:

• viewing MIME content, either in-line or by launching an external viewer?
• saving MIME content to a file?
• saving one part of a multipart message to a file?
• printing MIME content?

4.2 Does the UA support receiving these basic MIME content types? Does it display them in-line, and does it support printing them? If an external viewer is needed, is one pre-configured? Is the viewer included in the software distribution? 👑

In-line  Printing  External  Preconfig  Included
- text/plain
- text/enriched
- image/gif
- image/jpeg
- audio/basic
- video/mpeg
- application/octet-stream
- application/postscript
- message/rfc822
- message/partial

Does the UA support FTP and/or mail access for:

• message/external

Describe how the UA supports the basic multipart types:

• multipart/mixed
• multipart/parallel
• multipart/digest
• multipart/alternative

How does the UA handle:

• X-<bilateraly defined>
• unknown or unconfigured content types? 🤔

4.3 Does the UA let you configure receipt of additional content types? If so, describe the configuration procedure and what's possible. Is it complex or easy? Give an example configuration, and say whether you can add external viewers. For example: 💖

• application/wordperfect5.1
• application/msword
• multipart/appledouble (Macintosh systems only)

4.4 Does the UA support composing these basic MIME content types? Describe how easy or complex it is to compose a message with a MIME content type. 🎀

• text/plain
• text/enriched
• image/gif
• image/jpeg
• audio/basic
• video/mpeg
• application/octet-stream
• application/postscript
• message/rfc822
• message/partial
• message/external
• multipart/mixed
• multipart/parallel
• multipart/digest
• multipart/alternative

Does the UA generate X-<bilaterally defined> content types? When and why? 🧚

4.5 Does the UA support composing additional content types? If so, describe how to do it (configuration and/or composition). For example: ✨

• application/wordperfect5.1
• application/msword
• multipart/appledouble (Macintosh systems only)

4.6 Which content encodings does the UA support? 🌸

• 7bit
• quoted printable
• base64
• binary
• 8bit
• X-<bilateraly defined> (when and why)

4.7 What encoding is used for these content types? 🦋

  7bit QP   B64   Binary 8-bit Other
- text/plain
- text/enriched
- image/gif
- image/jpeg
- audio/basic
- video/mpeg
- application/octet-stream
- application/postscript
- message/rfc822
- message/partial
- message/external
- multipart/mixed
- multipart/parallel
- multipart/digest
- multipart/alternative

4.8 Does the UA generate the correct MIME version header? 💅

Mime-Version: 1.0

4.9 In multipart messages, give an example of the sort of boundary string that gets generated. 🔥

4.10 Does the UA support non-ASCII characters in headers, like in the subject or the free-form part of an address? 🌈

4.11 With the content type text/plain, you can have a charset parameter that says which character set is used. Which character sets (like iso-8859-1) does the UA support, either as standard or configurable? 💖

---

Security Considerations 🔐

Okay, this part is serious, bestie 😭 Testing a MIME UA against this checklist means dealing with the security risks described in the MIME specification, [RFC1521]. The biggest one is that automatically running general-purpose PostScript interpreters carries serious security risks. Please read RFC 1521 for more detail on these risks 🛡️💀

Author's Address 🖋️

Erik Huizer
SURFnet bv
P.O. Box 19035
3501 DA  Utrecht
The Netherlands

Phone: +31 30 305305
Fax: +31 30 305329
EMail: Erik.Huizer@SURFnet.nl

And that's the whole checklist, bestie!! 🌈✨👑