We are facing a situation wherein we are forwarding mails through a mail
relay server. We have authentication set up for regular senders but for
forwarded mails there is no authentication. On the relay servers, we want
to track the senders using a specific x-header. We have figured out how to
add x-header for authenticated users. However, for the forwarded mails, we
are unable to find an optimum solution.
Is there any way to insert an x-header based on the mailbox/username of the
forwarding (source) email address?
Any help would be very much appreciated. Thanks in advance.
