On 2008-04-26 at 10:09 -0400, Jayp wrote: > I'm trying to add a Sender header to my outgoing messages because one never
> shows up. I want the Sender email address to be the same as the Reply-To
> email address.
The Sender: header has a very specific meaning and you're trying to
subvert it. Exim will fix up a message when it's handling initial
submissions (local invocation, or "control = submission" in an ACL) and
this involves removing an existing Sender: header.
If you can state what the problem is you're trying to work around, that
might get more useful help.