I have set up sendmail on my OpenBSD 3.6 box to use masquerading. I've tested it and it works.
Mail from <email@example.com> gets rewritten as <firstname.lastname@example.org> which is what I want.
Now, when I invoke
the rewriting happens and sender and envelope sender are set correctly as <email@example.com>. However when I send mail using either mail or mutt sender and envelope sender show up as firstname.lastname@example.org
Mutt and mail both invoke sendmail so why this difference?