https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=36606 --- Comment #1 from Thomas Dukleth <td-koha-bugs@agogme.com> --- Remedies. These two options are not mutually exclusive. They are each additive. An intermediate mail server running free and open source software under direct Koha community control is important for reducing dependence upon and risk of interruption of service from any particular proprietary SMTP service enforcement of policy against excess bounce messages at particular time etc. Some external SMTP service dedicated to ensuring good email reputation is important in 2024 even if it would be unavoidably proprietary and there may be better choices than secure-mailgate.com. 1. Intermediate Mail Server providing Mail Relay to an External STMP Server. We can resolve the email authentication problem by sending messages first to a koha-community.org mail server with the primary purpose of providing authentication for email messages before relaying them to secure-mailgate which sends messages to their destination with better sender reputation than we would have ourselves. We discussed the issue at the last developer's meeting where I reported that I had investigated the problem and had a DKIM signing mail relay working with secure-mailgate.com with a test server using essentially Postfix running using DockerMailserver. Testing shows that delivery to Gmail passes all authentication tests for messages originating from the test03.agogme.com and then relaying them via secure-mailgate.com . I had set the DNS for secure-mailgate.com in same manner as the request for koha-community.org DNS changes with the exception that the sending mailserver m1.test03.agogme.com is set as the MX record for text03.agogme.com which primarily affects receiving email messages, not sending them. Choice of Docker Mailserver was the lightest weight choice for providing a Postfix relay service with confidence of ongoing development and bug fixes. See https://github.com/docker-mailserver/docker-mailserver . Aiding email collection for email based posting to Discourse with the inclusion of Dovecot and in Docker Mailserver is an added benefit. Antispam software such as Rspamd, SpamAssassin, etc. may be helpful in reducing the burden of email compatible use of Discourse. Unneeded software components are easily configured to disable what is unnecessary to reduce the resource use and it would be easy to add components to the Debian based system. In Docker Mailserver, there is no database use by default to reduce unnecessary resource use and greatly aid debugging. Consequently, a full service email system with many I first tested predominately Postfix Docker services including two good single person projects. There is no apparent bug list for Alpine GNU/Linux based docker-posfix, https://github.com/hmriit/docker-postfix-dkim . Postfix Relay also seemed too small for ongoing development such as testing for Debian 12, https://github.com/wader/postfix-relay/ . If we would need a full mail system running in a Docker container with many senders, a database based system such as Mailcow would be better, https://github.com/mailcow/mailcow-dockerized . [Mail servers may benefit more than some other systems from running directly on the host system, even in a chroot gaol, and not in a container for reliability. Configuration portability advantage of mail systems running in a container may be questionable even when they are full featured systems allowing arbitrary addition and modification. Beware that Docker services can easily become a black box which reports no helpful diagnostic information about a configuration typing error when failing and restarting every two seconds. I have successfully tested configuring Postfix inside docker-mailserver to support sender dependent relaying of mail including relaying via SMTPS port 465 for secure-mailgate.com without preventing other designated senders from sending mail directly without mail relays. 2. Alternative STMP Service. Further discussion of the issue at the Hackfest in Marseilles is leading people at HKS3 to explore a possible alternative to secure-mailgate.com which provides more services generally. Many SMTP services provide DKIM message signing and hosting authentication certificates generally available for secure-mailgate.com . However, as a free software project and in the interest of being in control of systems and not subject to termination or suspension of services which cannot be replaced quickly enough we should be aiming to reduce or eliminate dependency upon proprietary services. Particularly with implementing Discourse, there are scenarios such as email addresses used by spammers for unsatisfied account registration; sending an essential message to all users; etc. which may result in temporary excess bounces leading to account suspension or cancellation with a proprietary SMTP providers. -- You are receiving this mail because: You are watching all bug changes.