User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030703 When in a mixed Outlook/Mozilla environment, Mozilla's "Sender" column can display misleading information. Example: When a meeting is scheduled through Outlook 2002/Exchange, appointment notices are sent to all participants. When one of these notices is forwarded (from within Outlook) to another recipient, the Sender: header is set to the person sending the message, but the From: header remains set to the original "author" of the meeting. When viewed in Outlook, the header is displayed as "From: (forwarder) on behalf of (original author)". Mozilla 1.4 displays this as "From: (original author)", with no mention anywhere of the forwarder. (Except by displaying full headers, revealing the Sender: field.) The From:/Sender: header differences are mentioned later in the comments on bug 40934, but in the context of filtering messages. I'd like to suggest Mozilla follow Outlook's "on behalf of" example when both a From: and a Sender: header are present (and different). Reproducible: Always Steps to Reproduce:

Let's take a look at this for 1.8. If anyone knows of any relevant RFC's that talk about combining the two into a "on behalf of" string please chime in.

After doing a quick Google search and following some of the discussion around this, perhaps an interim workaround would be in order. Since it does not look like there would be an easy way to standardize on headers, could we allow a mapping of headers to other headers (for display and/or filter purposes)? Just a thought.

*** Bug 253924 has been marked as a duplicate of this bug. ***

This is actually a reasonably important bug in terms of the Sender Authentication work going on in the email industry right now. Both Sender ID (the IETF MARID group) and DomainKeys (being championed by Yahoo), use the Sender: header in authenticating mail (and in both cases, the From: is overridden in authentication by the Sender: header). If the Sender: header is authenticated by a MTA, but is not shown, the user may be fooled: Sender: badguy@evilphisher.co From: security@bigbank.co Subject: Update your account Dear user, Please click on the following link to update your account details... In the above mail, currently the From address will only be shown, whereas the user should really be advised that its badguy@evilphisher.co that is injecting the message. The 'on behalf of' concept is not part of an RFC -- it was Outlook's User Interface guys solution. Their rule appears to be to show $sender on behalf of $from. IMHO, mozilla would should show follow outlook's model in the message window, and choose which address to show in the folder list of messages based on the authenticated address that the Authentication-Results: header says (from http://www.ietf.org/internet-drafts/draft-kucherawy-sender-auth-header-00.txt). If that header is not there (which will be likely for a while, but the draft above was done by Sendmail :), then I'd show Sender then From in the list view.

i think this is going to end up being a dupe of the sender fix for Bug #285474 *** This bug has been marked as a duplicate of 285474 ***