From 4c7cdeb43bfede6d296c9de6132771e647bf0214 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Tim=20M=C3=B6hlmann?= Date: Mon, 31 Dec 2018 04:13:25 +0200 Subject: [PATCH] FAQ: Difference between DOMAINS and HOSTNAMES - Closes #742 - Closes #747 --- docs/faq.rst | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/docs/faq.rst b/docs/faq.rst index 395b739c..7849d7c5 100644 --- a/docs/faq.rst +++ b/docs/faq.rst @@ -89,6 +89,51 @@ our ongoing `project management`_ discussion issue. Deployment related ------------------ +What is the difference between DOMAIN and HOSTNAMES? +```````````````````````````````````````````````````` + +Similair questions: + +- Changing domain doesn't work +- Do I need a certificate for ``DOMAIN``? + +``DOMAIN`` is the main mail domain. Aka, server identification for outgoing mail. DMARC reports point to ``POSTMASTER`` @ ``DOMAIN``. +These are really the only things it is used for. You don't need a cert for ``DOMAIN``, as it is a mail domain only and not used as host in any sense. +However, it is usual that ``DOMAIN`` gets setup as one of the many mail domains. None of the mail domains ever need a certificate. +TLS certificates work on host connection level only. + +``HOSTNAMES`` however, can be used to connect to the server. All host names supplied in this variable will need a certificate. When ``TLS_FLAVOR=letsencrypt`` is set, +a certificate is requested automatically for all those domains. + +So when you have something like this: + +.. code-block:: bash + + DOMAIN=example.com + POSTMASTER=me + HOSTNAMES=mail.example.com,mail.foo.com,bar.com + TLS_FLAVOR=letsencrypt + +- You'll end up with a DMARC address to ``me@example.com``. +- Server identifies itself as the SMTP server of ``@example.com`` when sending mail. Make sure your reverse DNS hostname is part of that domain! +- Your server will have certificates for the 3 hostnames. You will need to create ``A`` and ``AAAA`` records for those names, + pointing to the IP addresses of your server. +- The admin interface generates ``MX`` and ``SPF`` examples which point to the first entry of ``HOSTNAMES`` but these are only examples. + You can modify them to use any other ``HOSTNAMES`` entry. + +You're mail service will be reachable for IMAP, POP3, SMTP and Webmail at the addresses: + +- mail.example.com +- mail.foo.com +- bar.com + +.. note:: + + In this case ``example.com`` is not reachable as a host and will not have a certificate. + It can be used as a mail domain if MX is setup to point to one of the ``HOSTNAMES``. However, it is possible to include ``example.com`` in ``HOSTNAMES``. + +*Issue reference:* `742`_, `747`_. + How does Mailu scale up? ```````````````````````` @@ -154,6 +199,8 @@ correct syntax. The following file names will be taken as override configuration .. _`165`: https://github.com/Mailu/Mailu/issues/165 .. _`177`: https://github.com/Mailu/Mailu/issues/177 .. _`332`: https://github.com/Mailu/Mailu/issues/332 +.. _`742`: https://github.com/Mailu/Mailu/issues/742 +.. _`747`: https://github.com/Mailu/Mailu/issues/747 .. _`520`: https://github.com/Mailu/Mailu/issues/520 .. _`591`: https://github.com/Mailu/Mailu/issues/591