| We all know and use it, but here is a formal specification. |
| Each message is a stream of 7-bit ASCII chars which contains a header and optional (newline separated) body. |
| Header consists of a set of entries with one entry per line given by a colon separated key:value pair. |
| Key contains no spaces or tabs and cannot exceed 63 chars. |
| Body is a fully unstructured sequence of ASCII chars. |
| There is a finite set of standard keys and an extension mechanism via the "X"-prefix. The standard set (as used by MH) is: |
| Date Bcc Resent-Date Resent-Fcc |
| From Fcc Resent-From resent- |
| Sender Message-ID Resent-To Message-Id |
| To Subject Resent-cc Forwarded |
| cc In-Reply-To Resent-Bcc Replied |