Electronic mail has a standardized syntax for text messages that
are sent across networks. The standard syntax is described in RFC
822. Messages have an envelope and contents. Envelopes contain all
necessary information to accomplish transmission and delivery of the
message content. The fields within the envelope are in a standard
format.
In most cases, the IBM-supplied mail header defaults are adequate.
To understand the IBM-supplied mail header defaults, see Default SMTP rules. If it is necessary
for you to change them, you can use the REWRITE822HEADER statement
in the SMTP configuration data set to control the way SMTP performs
a rewrite of the RFC 822 mail headers. Mail headers are passed from
the local system, or NJE network, to the TCP network. Mail headers
passing from the TCP network to the local system or NJE network are
not affected. Only the addresses under certain RFC 822 header fields
can be subject to the header rewriting rules.
The header fields affected by the REWRITE822HEADER statement are:
- Field
- Description
- From
- The identity of the person sending the message.
- Resent-From
- Indicates the person that forwarded the message.
- Reply-To
- Provides a mechanism for indicating any mailboxes to which responses
are to be sent.
- Resent-Reply-To
- Indicates the person to whom you should forward the reply.
- Return-Path
- This field is added by the mail transport service at the time
of final delivery. It contains definitive information about the address
and route back to the originator of the message.
- Sender
- The authenticated identity of the agent that sent the message.
An agent can be a person, system, or process.
- Resent-Sender
- The authenticated identity of the agent that has resent the message.
- To
- Contains the identity of the primary recipient of the message.
- Cc
- Contains the identity of the secondary (informational) recipients
of the message.
- Bcc
- Contains the identity of additional recipients of the message.
The contents of this field are not included in copies sent to the
primary and secondary recipients of the message but are included in
the author’s copy.