PMDF System Manager's Guide


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20.1.4 Header Lines in Messages

PMDF uses two sources of information to construct message headers for messages it receives from VMS MAIL. The first is VMS MAIL itself, which provides a To:, From:, Cc:, and Subject: line, and a list of addressees. The second source of information consists of logical names which you can define yourself. The following logical names can be defined to create header lines:
  ° PMDF_COMMENTS (*) ° PMDF_READ_RECEIPT_TO
  ° PMDF_DELIVERY_RECEIPT_TO ° PMDF_REFERENCES (*)
  ° PMDF_ERRORS_TO (*) ° PMDF_REPLY_TO (*)
  ° PMDF_FROM ° PMDF_RESENT_FROM
  ° PMDF_HEADER ° PMDF_RESENT_REPLY_TO
  ° PMDF_HEADER_n ° PMDF_SENSITIVITY (*)
  ° PMDF_IMPORTANCE (*) ° PMDF_TIMEZONE
  ° PMDF_KEYWORDS (*) ° PMDF_WARNINGS_TO (*)
  ° PMDF_ORGANIZATION (*) ° PMDF_X_FAX_DEFAULTS (*)
  ° PMDF_PRIORITY (*) ° PMDF_X_PS_QUALIFIERS (*)
The logical names marked with an asterisk, *, are described in the PMDF User's Guide; the remaining logicals and associated header lines are described below.

The PMDF_TIMEZONE logical name is set by the system manager in the system logical name table to translate to the system's local timezone; users can only override this setting if no system PMDF_TIMEZONE logical is set. None of the other logical names are set by default, and even if they are, users can define their own overriding values to customize the headers attached to the messages they send.

When changing the value of the PMDF_TIMEZONE logical, note that this logical is normally defined at system startup by the SYS$STARTUP:pmdf_startup.com procedure created when PMDF was installed; see the OpenVMS edition of the PMDF Installation Guide.

After changing the value of the PMDF_TIMEZONE logical, the Dispatcher should be restarted so that services under the Dispatcher will be made aware of the change and properly use the new value.

Note

If the PMDF_TIMEZONE logical does not exist (for example if you choose to deassign it in pmdf_com:pmdf_site_startup.com), then PMDF looks for the following system logicals to determine the local time zone. First it looks for SYS$LOCALTIME, then if that is not defined, it looks for SYS$TIMEZONE_DIFFERENTIAL and SYS$TIMEZONE_NAME.

20.1.4.1 Cc: Header Lines

Cc: header lines are produced in outgoing mail when a recipient address is passed to PMDF by VMS MAIL and the address can be matched with the text that appears on the VMS MAIL Cc: line. The addresses on the VMS MAIL Cc: line itself cannot be used directly; they are not suitable for use on a RFC 822 Cc: line and are used to construct an X-VMS-Cc: line instead.

VMS MAIL provides no indication of where the envelope addresses it passes to PMDF came from (To: line, Cc: line, or both). PMDF tries to match the address with the contents of the X-VMS-To: and X-VMS-Cc: lines, but this attempt is necessarily imperfect and can fail. If it does fail and PMDF cannot localize an address it will be placed on the To: line by default. The result is that addresses that originated on the VMS MAIL Cc: line can end up on the outgoing message's To: header.

20.1.4.2 Content-transfer-encoding: Header Lines

PMDF will insert a Content-transfer-encoding: header that describes the encoding applied to the data in outgoing messages. This is normally 7BIT for messages containing only 7 bit text data and 8BIT for messages containing 8 bit text data. Messages sent with SEND/FOREIGN will normally be encoded using the MIME-compliant BASE64 encoding and will be labelled accordingly. The Content-transfer-encoding: header is defined by MIME (RFCs 2045-2049); it is not part of RFC 822.

20.1.4.3 Content-type: Header Lines

PMDF will insert a Content-type: header into outgoing messages that describes the type of data being sent. Most messages sent from VMS MAIL will be labelled as "text/plain" along with whatever character set is specified by the charset7 or charset8 channel keywords on the local channel. Files sent with SEND/FOREIGN will be labelled as "application/vms-rms" if no special RMS semantics are attached. Currently the only RMS semantics that are recognized are DDIF, DOTS, and DTIF; these are labelled as "application/ddif", "application/dots", and "application/dtif" respectively. In any of these cases the Content-type: header will also contain a VMS-FDL parameter containing an FDL description of the file.

When a message labelled as "application/vms-rms" or any of the special semantic tags is received by VMS MAIL the encoding will be reversed and the stored FDL information will be applied to the message as it is delivered. The result will be a foreign format message whose file attributes and contents are preserved.

20.1.4.4 Delivery-receipt-to: Header Lines

The use and construction of Delivery-receipt-to: headers is discussed in Section 20.3.

20.1.4.5 Disposition-notification-to: Header Lines

The use and construction of Disposition-notification-to: headers is discussed in Section 20.3.

20.1.4.6 From: and Sender: Header Lines

The From: header is constructed by translating the logical name PMDF_FROM. If it is defined, its equivalence string is used as the From: address for the message and the authenticated address of the person sending the message is placed on a Sender: line in the message header.

If the PMDF_FROM line does not translate to anything (by default it will not), the address of the person sending the message is used as the From: address and no Sender: line is inserted in the message header.

The setting of PMDF_FROM is ignored when messages pass through VMS MAIL because of automatic forwarding. Addresses specified by the PMDF_FROM logical undergo normal PMDF address rewriting; they are not exempt from rewrite processing.

If PMDF_FROM translates to a string beginning with and ending in a question mark "?", PMDF will take the enclosed string and prompt the user with it. Whatever the user types will be placed on the From: header line. This prompt will appear after any message has been entered.

Prompting is only possible in regular command-oriented VMS MAIL; it cannot be done in DECwindows MAIL. PMDF checks to make sure that prompting is possible and will ignore any requests for prompts in environments that don't support it.

20.1.4.7 Read-receipt-to: Header Lines

The use and construction of Read-receipt-to: headers is discussed in Section 20.3.

20.1.4.8 Resent-date: Header Lines

A Resent-date: line is created when a message being delivered by PMDF to VMS MAIL is forwarded back to PMDF by some type of VMS MAIL forwarding (usually a SET FORWARD to an IN% address). Such a message already has a Date: header, so PMDF adds a Resent-date: instead. The format of a Resent-date: header is the same as a Date: header. If both a Date: and Resent-date: header are already present no time stamp information is added apart from the Received: line (multiple Resent-date: headers are not legal RFC 822 syntax).

20.1.4.9 Resent-from: Header Lines

Resent-from: headers and the associated PMDF_RESENT_FROM logical are handled in the same way as From: and PMDF_FROM, with the exception that forwarding does not affect these headers in the same way that it affects From: headers.

20.1.4.10 Resent-reply-to: Header Lines

Resent-reply-to: headers and the associated PMDF_RESENT_REPLY_TO logical are handled in the same way as Reply-to: and PMDF_REPLY_TO, with the exception that forwarding does not affect these headers in the same way that it affects Reply-to: headers.

20.1.4.11 Resent-to: Header Lines

A Resent-to: line is created when a message being delivered by PMDF to VMS MAIL is forwarded back to PMDF by some type of VMS MAIL forwarding (usually a SET FORWARD to an IN% address) and the message already has a To: header. In this case the text that would normally be placed on the To: header is placed on the Resent-to: header line instead.

No logical name is provided to set this header.

20.1.4.12 Subject: Header Lines

The Subject: header line is obtained directly from VMS MAIL (which has either constructed it itself or gotten it from the user).

20.1.4.13 To: Header Lines

To: header lines are produced in outgoing mail when a recipient address is passed to PMDF by VMS MAIL and the address can be matched with the text that appears on the VMS MAIL To: line. The addresses on the VMS MAIL To: line itself cannot be used directly; they are not suitable for use on the To: line and are used to construct an X-VMS-To: line instead.

VMS MAIL provides no indication of where the envelope addresses it passes to PMDF came from (To: line, Cc: line, or both). PMDF tries to match the address with the contents of the X-VMS-To: and X-VMS-Cc: lines, but this can fail. If it does fail PMDF places the address on the To: line by default. The result is that addresses that originated on the VMS MAIL Cc: line can end up on the outgoing message's To: header.

20.1.4.14 X-Envelope-to: Header Lines

The X-Envelope-to: header line contains a duplicate of the address that appears in the message envelope. This header line is used by PMDF to reconstruct envelope addresses that have been damaged by various transport mechanisms (notably BITNET and NJE, which truncate envelope addresses to eight characters). The X-Envelope-to: line for a particular copy of a message contains only the address that that particular copy is being sent to; it does not contain all the addresses on the To: line (except in the simplest case where only a single copy of the message is needed).

The X-Envelope-to: line is not user-settable. Its presence or absence in a particular copy of a message is controlled by the x_env_to, single, and nox_env_to keywords on the corresponding channel; see Section 2.3.4.61.

X-Envelope-to: lines are unique among header lines in that they are completely replaced each time a message is enqueued by PMDF. (Most other header lines are cumulative.) An X-Envelope-to: header line only reflects the most recent envelope destination in the case of forwarding. The diagnostic usefulness of an X-Envelope-to: header line has been almost entirely superseded by the use of "received for" clauses in Received: header lines and NOTARY notification messages including final-recipient information.

Note

X-Envelope-to: header lines are an extension to RFC 822.

20.1.4.15 X-VMS-Cc: Header Lines

VMS MAIL's Cc: line (which is not in RFC 822 format) is placed on the X-VMS-Cc: line of the message header. See Section 20.1.4.1.

Note

X-VMS-Cc: header lines are an extension to RFC 822.

20.1.4.16 X-VMS-To: Header Lines

VMS MAIL's To: line (which is not in RFC 822 format) is placed on the X-VMS-To: line of the message header. See Section 20.1.4.13.

Note

X-VMS-To: header lines are an extension to RFC 822.


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