dkim: document dkim-use-domain

[pmg-docs.git] / pmgconfig.adoc

diff --git a/pmgconfig.adoc b/pmgconfig.adoc
index 38c7a3aed94f67553f6c9a9312f58ce879cb0b87..8035923840334e85c4b69ff9355c15cbf72c2cf6 100644 (file)
--- a/pmgconfig.adoc
+++ b/pmgconfig.adoc
@@ -585,6 +585,18 @@ Controls whether all outbound mail should get signed or only mails from domains
 listed in `/etc/pmg/dkim/domains`, if it exists and `/etc/pmg/domains`
 otherwise.
 
+Select Signing Domain::
+
+Determines whether to DKIM sign emails using the domain found in the envelope
+from or the from header in the body of the email. The envelope from is also
+known as reverse-path, see {smtp_rfc} section 3.3 and {rfc_5322} section 3.6.2.
++
+The envelop from of certain emails, bounces for example, can be empty. In these
+cases it is desirable to sign them using the domain found in the from header.
++
+Additionally, DMARC (see {dmarc_rfc} section 3.1.1) needs the domain found in
+the from header in certain situations.
+
 These settings are saved to the 'admin' subsection in `/etc/pmg/pmg.conf`,
 using the following configuration keys: