> > > It isn't just Postfix, many MTAs do that. > > "To: arnt" isn't legal syntax today, but it was legal a few decades ago > and quite commonly used for years after the syntax changed (in, IIRC, 1982) > and various MTAs still contains glue to support that. I think that's mostly > a bug these days. It landed on the wrong side of the fence when servers > learnt to distinguish between their own users (for whom they will relay) > and others. > >
yes, which is a pita if the clients set the "To:" to something like "undisclosed-recipients" for mailings with recipients in "BCC", because it then adds the hostname of the server (which may be different then the sender-domain).
