Joaquin F:
> This is more a curiosity than a real need, but I was wondering why I can't
> modify the "From" header when sending mails between local users.
man 5 header_checks
Many people overlook the main limitations of header and body_checks
rules.
...
Message headers added by the cleanup(8) daemon itself are excluded from
inspection. Examples of such message headers are From:, To:, Mes-
sage-ID:, Date:.
header_checks will inspect only headers that are actually part of
the message when Postfix receives it.
Wietse
