Pass parameters without executing them
03Parameters identify the root and can carry application-specific auxiliary information. Their syntax and their interpretation are different concerns.
The agent provides the parameters and associated parts to the application. Interpretation follows that application’s format and safety rules; no command or file access is performed by this teaching example.
Source for this drawing: RFC 2387 · Read RFC section 3.3 ↗
New to this? Start hereA quick picture + helpful background
A message needs an address.
Think of a packet as a small addressed envelope. Devices pass it onward; transport protocols decide what delivery promises an application gets.
Helpful first, if these ideas are unfamiliar
These pictures are analogies to help you learn. The linked RFC explains the actual rules.
Terms in this drawing
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
Parameter order is independent. MIME parameter quoting is needed for special characters such as the slash in text/html and angle brackets in a Content-ID.
- Parameter order is independent. MIME parameter quoting is needed for special characters such as the slash in text/html and angle brackets in a Content-ID.
- start-info can carry a string or refer to auxiliary MIME content. A first non-whitespace character of < indicates a reference.
- The using application must define start-info interpretation; the user agent supplies its value. A string in a message is not permission to execute a command.
Fictional .example identifiers and omitted payloads. These are simplified illustrations, not complete importable messages or a full MIME parser.
Read the RFC section ↗