diff --git a/docs/faq.rst b/docs/faq.rst
index c4cea444..403fd163 100644
--- a/docs/faq.rst
+++ b/docs/faq.rst
@@ -261,6 +261,8 @@ correct syntax. The following file names will be taken as override configuration
    - ``main.cf`` as ``$ROOT/overrides/postfix/postfix.cf``
    - ``master.cf`` as ``$ROOT/overrides/postfix/postfix.master``
    - All ``$ROOT/overrides/postfix/*.map`` files
+   - For both ``postfix.cf`` and ``postfix.master``, you need to put one configuration per line, as they are fed line-by-line
+     to postfix.
 - `Dovecot`_ - ``dovecot.conf`` in dovecot sub-directory;
 - `Nginx`_ - All ``*.conf`` files in the ``nginx`` sub-directory;
 - `Rspamd`_ - All files in the ``rspamd`` sub-directory.