I have been trying to resolve for a couple of months using multiple different configurations.
The local delivery to a Dovecot mailbox (originalto@domain.org) keeps the original sender (sender@gmail.com) in the FROM address. The remote delivery using SendGrid SMTP server via a virtual forward to (receiver@gmail.com) works if:
in smtp_header_checks if there is
/^From:(.*)$/ REPLACE From: no-reply@domain.org
and in main.cf
sender_canonical_classes = envelope_sender
smtp_header_checks = regexp:/etc/postfix/smtp_header_checks
I have tried to add a reply-to to the header so that the receivers, who get the forwarded email, can reply to it.
In smtp_header_checks I put
/^From:(.*)$/ REPLACE Reply-To:$1<br>
/^From:(.*)$/ REPLACE From: no-reply@domain.org
but this gives a 550 Error
Feb 14 13:40:03 club-jowett-vm postfix/smtp[12857]: BB2AD65E91: replace: header From: <sender@gmail.com>: From: no-reply@domain.org Reply-To: <sender@gmail.com>
Feb 14 13:40:03 t-vm postfix/smtp[12857]: BB2AD65E91: to=<receiver@gmail.com>, orig_to=<originalto@domain.org>, relay=smtp.sendgrid.net[54.228.39.88]:587, delay=2.3, delays=1.6/0.19/0.48/0.05, dsn=5.0.0, status=bounced (host smtp.sendgrid.net[54.228.39.88] said: 550 The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements (in reply to end of DATA command))
I have tried other configurations one of which added the reply-to but some receivers rejected the email because of multiple ReplyTo headers.
I have also tried /^From:(.*)$/ PREPEND Reply-To:$1
which gives the same 550 error.
Has anyone a configuration that works, please?
