Mail Settings
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- RFC 5322 – Internet Message Format (2008) This is the current standard that defines the structure of email messages. It explicitly states that the
From:header field must appear exactly once in a message.- Section 3.6.2 of RFC 5322:
“The ‘From’ field specifies the author(s) of the message. The ‘From’ field must contain exactly one mailbox.” “The ‘From’ field must be present in every message.”
- Section 3.6.2 of RFC 5322:
- RFC 5322 – Internet Message Format (2008) This is the current standard that defines the structure of email messages. It explicitly states that the
This RFC was not previously enforced at Eskimo North. However, because phishing scams, people forging e-mail with From addresses appearing to be from your bank or other security sensitive addresses intending to trick you into revealing authentication information that could result in your account being cleaned out, have been taking advantage of a quirk in many mailers that will show the last From: line as the From address regardless of what is in the actual headers, we have begun to enforce this requirement.
This breaks forwarding from sites that do not follow the RFC and fail to escape the From: line in forwarded e-mail. The method of escape is unimportant but the generally accepted method is to add: ‘>’ before each line of the forwarded message, however, for the purposes of this RFC only the From: line need be escaped.
Thus if you are forwarding e-mail from Gmail or similar RFC non-compliant mail system, you can get around this by manually adding a ‘>’ in front of the From: line in the forwarded content before sending.
Some spammers use a technique of using a one-time bogus address in the header but then including the desired address in a separate From: line, these new filters will also cause their e-mails to be rejected.