The duplicate Sender header was mainly coming from announce-list resends. It was helpfully added by perl's Mail::Internet package.
The mailing list software has been modified to delete incoming Sender header fields when it sees them which should result only one Sender: header in mail to the list. On Mon, May 06, 2019 at 04:02:55PM -0400, sourcemaster wrote: >Please use postmaster (cc'ed), not sourcemaster, for email issues. >See: RFC 822. > >On Mon, May 06, 2019 at 03:51:21PM -0400, Chris Wagner wrote: >>Maintainers, I have been getting numerous bounce warnings and spam >>holds on mail sent to me by the Cygwin list. The spam holds are due >>to protocol violations. This ezmlm warning is because of: 550 >>Messages should have one or no Sender headers, not 2. >> >>If the list software could be made more compliant or I could be >>informed about some loosened setting on my spam panel. >> >>Thanks. >> >> >> >>On 2019-05-06 2:22 pm, cygwin-help wrote: >>>Hi! This is the ezmlm program. I'm managing the >>>cygwin mailing list. >>> >>> >>>Messages to you from the cygwin mailing list seem to >>>have been bouncing. I've attached a copy of the first bounce >>>message I received. >>> >>>If this message bounces too, I will send you a probe. If the probe >>>bounces, >>>I will remove your address from the cygwin mailing list, >>>without further notice. >>> >>> >>>I've kept a list of which messages from the cygwin mailing list have >>>bounced from your address. >>> >>>Copies of these messages may be in the archive. >>>To retrieve a set of messages 123-145 (a maximum of 100 per request), >>>send an empty message to: >>> <cygwin-get.123_145@> >>> >>>To receive a subject and author list for the last 100 or so messages, >>>send an empty message to: >>> <cygwin-index@> >>> >>>Here are the message numbers: >>> >>> 216505 >>> 216503 >>> 216515 >>> 216521 >>> 216525 >>> 216526 >>> 216529 >>> 216533 >>> 216540 >>> 216556 >>> 216557 >>> 216558 >>> 216559 >>> 216560 >>> 216561 >>> 216563 >>> 216564 >>> 216562 >>> 216571 >>> 216574 >>> 216575 >>> 216583 >>> 216579 >>> 216585 >>> 216586 >>> 216580 >>> 216587 >>> 216588 >>> 216590 >>> 216582 >>> 216584 >>> 216591 >>> 216589 >>> 216581 >>> 216594 >>> 216595 >>> 216598 >>> 216599 >>> 216601 >>> 216602 >>> 216600 >>> 216603 >>> 216604 >>> 216614 >>> 216623 >>> 216616 >>> 216615 >>> 216618 >>> 216619 >>> 216620 >>> 216621 >>> 216622 >>> >>>--- Enclosed is a copy of the bounce message I received. >>> >>>Return-Path: <> >>>Received: (qmail 67289 invoked for bounce); 24 Apr 2019 18:35:31 -0000 >>>Date: 24 Apr 2019 18:35:31 -0000 >>>From: mailer-dae...@sourceware.org >>>To: cygwin-return-216505-@ >>>Subject: failure notice >>> >>>Hi. This is the qmail-send program at sourceware.org. >>>I'm afraid I wasn't able to deliver your message to the following >>>addresses. >>>This is a permanent error; I've given up. Sorry it didn't work out. >>> >>><wagnerc@>: >>>User and password not set, continuing without authentication. >>><wagnerc@> 69.64.57.52 failed after I sent the message. >>>Remote host said: 550 Messages should have one or no Sender >>>headers, not 2. >> -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
