Technical data

6.3.3 How the IMAP Server Handles Foreign Message Formats
The IMAP Server determines the correct format for common file types.
It does this by checking the beginning of the file for a recognizable
file header that matches a set contained in the configuration file
TCPIP$IMAP_HOME:TCPIP$IMAP_MAGIC.TXT (analogous to the magic files
found on UNIX systems). If a matching file header is found, the server can let the
client know the MIME type and subtype of the file.
6.3.4 Understanding IMAP Message Headers
Mail message headers sent by the IMAP Server must conform to the standard
specified in RFC 822. Because many of the messages received on an OpenVMS
system are not in the RFC 822, or Internet, format (for example, DECnet mail or
mail from another message transport system), the IMAP Server builds a new set
of headers for each message that is not RFC 822 format and that is based on the
OpenVMS message headers.
Table 6–6 describes the headers on mail messages that are forwarded by the
IMAP Server.
Table 6–6: IMAP Server Forwarded Message Headers
IMAP Message Header
Obtained From
Date: Arrival date of message. Changed to
Internet format, which shows the day of the
week,thedate,thetime,andthetimezone
offset from Greenwich Mean Time (GMT).
An example of the format is Wed, 30 May
01 16:19:53 +0100.
From: OpenVMS message
From:
field. Rebuilt to
ensure RFC 822 compatibility.
To: OpenVMS Mail
To:
field. Rebuilt to ensure
RFC 822 compatibility.
CC: OpenVMS Mail
CC:
field. Rebuilt to ensure
RFC 822 compatibility.
Subject: OpenVMS Mail
Subj:
field. Accented
characters are RFC 2047 encoded, but the
change is not visible to users because IMAP
clients reverse the encoding.
X-VMS-From: OpenVMS Mail
From:
field. Not rebuilt.
X-IMAP4-Server: Server host name and IMAP version
information. Sent only if configuration
option Send-ID-Headers is set to True.
X-IMAP4-ID: Message UID. Sent only if configuration
option Send-ID-Headers is set to True.
The IMAP Server sends these message headers to the IMAP Client unless both of
the following conditions are true:
• The configuration option Ignore-Mail11-Headers is set to True or is not defined.
• The message text starts with SMTP headers.
6.3.5 How IMAP Rebuilds OpenVMS Mail Address Fields
It is important for the IMAP Server to rebuild the
From:
header, because this
header can be used as a destination address if a reply is requested from the IMAP
6–8 Mail Services