My understanding of the SMTP protocol is that a message destined for many
recipients will result in several "RCPT TO" lines during the initial
handshake and the receiving server will then save a separate unique copy for
each recipient.
Mercury does this but it is not required by the RFC to do this. Many older SMTP systems same message to each mailbox, nothing in the RFC 2822 headers then will indicate the original RCPT TO: addresses.
The fact that Mercury can write an "X-Envelope-To" header
means that it could equally well write a standards compliant
"Received:" line.
Mercury is writing a standards compliant Received line. It is an SMTP server operating IAW RFC 2821. There is no requirement that I can find in RFC 2821 to add the RCPT TO: address to any RFC 2822 message Received: line. There is a section in the RFC that talks gatewaying and adding the original SMTP addresses to the RFC 2822 message body. I personally consider mail going from the SMTP to the POP3 system mail gatewaying, many do not..
3.8.1 Header Fields in Gatewaying
Header fields MAY be rewritten when necessary as messages are
gatewayed across mail environment boundaries. This may involve
inspecting the message body or interpreting the local-part of the
destination address in spite of the prohibitions in section 2.4.1.
Other mail systems gatewayed to the Internet often use a subset of
RFC 822 headers or provide similar functionality with a different
syntax, but some of these mail systems do not have an equivalent to
the SMTP envelope. Therefore, when a message leaves the Internet
environment, it may be necessary to fold the SMTP envelope
information into the message header. A possible solution would be to
create new header fields to carry the envelope information (e.g.,
"X-SMTP-MAIL:" and "X-SMTP-RCPT:"); however, this would require
changes in mail programs in foreign environments and might risk
disclosure of private information (see section 7.2).
Our mail client is standards compliant but unfortunately cannot be changed
to cope with non-standard headers.
What mail client? What standards compliant headers specified by RFC 2821 does this mail client support?
Is there a mechanism to feed change requests back to the author?
If you can cite an RFC that provides a requirement for anything I'm quite sure that David Harris would change the program to bring it into compliance.
<blockquote><p>My understanding of the SMTP protocol is that a message destined for many
recipients will result in several "RCPT TO" lines during the initial
handshake and the receiving server will then save a separate unique copy for
each recipient.</p></blockquote><p>Mercury does this but it is not required by the RFC to do this.&nbsp; Many older SMTP systems same message to each mailbox, nothing in the RFC 2822 headers then will indicate the original RCPT TO: addresses.
</p><blockquote><p>The fact that Mercury can write an&nbsp; "X-Envelope-To" header
means that it could equally well write a standards compliant
"Received:" line.</p></blockquote><p>Mercury is writing a standards compliant Received line. &nbsp; It is an SMTP server operating IAW RFC 2821.&nbsp; There is no requirement that I can find in RFC 2821 to add the RCPT TO: address to any RFC 2822 message Received: line.&nbsp; There is a section in the RFC that talks gatewaying and adding the original SMTP addresses to the RFC 2822 message body.&nbsp; I personally consider mail going from the SMTP to the POP3 system mail gatewaying, many do not.. </p><pre><font size="2" face="courier new,courier">3.8.1 Header Fields in Gatewaying
Header fields MAY be rewritten when necessary as messages are
gatewayed across mail environment boundaries. This may involve
inspecting the message body or interpreting the local-part of the
destination address in spite of the prohibitions in section 2.4.1.
Other mail systems gatewayed to the Internet often use a subset of
RFC 822 headers or provide similar functionality with a different
syntax, but some of these mail systems do not have an equivalent to
the SMTP envelope. Therefore, when a message leaves the Internet
environment, it may be necessary to fold the SMTP envelope
information into the message header. A possible solution would be to
create new header fields to carry the envelope information (e.g.,
"X-SMTP-MAIL:" and "X-SMTP-RCPT:"); however, this would require
changes in mail programs in foreign environments and might risk
disclosure of private information (see section 7.2).</font>
</pre><blockquote><p>Our mail client is standards compliant but unfortunately cannot be changed
to cope with non-standard headers. </p></blockquote><p>What mail client?&nbsp; What standards compliant headers specified by RFC 2821 does this mail client support?
</p><blockquote><p>Is there a mechanism&nbsp; to feed change requests back to the author?</p></blockquote><p>If you can cite an RFC that provides a requirement for anything I'm quite sure that David Harris would change the program to bring it into compliance.
</p>
