4.4.4. AUTOMATIC USE OF FROM / SENDER / REPLY-TO

For systems which automatically generate address lists for replies to messages, the following recommendations are made:

• The "Sender" field mailbox should be sent notices of any problems in transport or delivery of the original messages. If there is no "Sender" field, then the "From" field mailbox should be used.

• The "Sender" field mailbox should NEVER be used automatically, in a recipient's reply message.

• If the "Reply-To" field exists, then the reply should go to the addresses indicated in that field and not to the address(es) indicated in the "From" field.

• If there is a "From" field, but no "Reply-To" field, the reply should be sent to the address(es) indicated in the "From" field.

Sometimes, a recipient may actually wish to communicate with the person that initiated the message transfer. In such cases, it is reasonable to use the "Sender" address.

This recommendation is intended only for automated use of originator-fields and is not intended to suggest that replies may not also be sent to other recipients of messages. It is up to the respective mail-handling programs to decide what additional facilities will be provided.

Examples are provided in Appendix A.