4.2. FORWARDING

Some systems permit mail recipients to forward a message, retaining the original headers, by adding some new fields. This standard supports such a service, through the "Resent-" prefix to field names.

Whenever the string "Resent-" begins a field name, the field has the same semantics as a field whose name does not have the prefix. However, the message is assumed to have been forwarded by an original recipient who attached the "Resent-" field. This new field is treated as being more recent than the equivalent, original field. For example, the "Resent-From", indicates the person that forwarded the message, whereas the "From" field indicates the original author.

Use of such precedence information depends upon participants' communication needs. For example, this standard does not dictate when a "Resent-From:" address should receive replies, in lieu of sending them to the "From:" address.

Note: In general, the "Resent-" fields should be treated as containing a set of information that is independent of the set of original fields. Information for one set should not automatically be taken from the other. The interpretation of multiple "Resent-" fields, of the same type, is undefined.

In the remainder of this specification, occurrence of legal "Resent-" fields are treated identically with the occurrence of fields whose names do not contain this prefix.