What is the
smtp_domain in the GitLab configuration? There is also a
smtp_user_name; so what would you put in the
Contrary to what the examples on GitLab Omnibus
SMTP lead you to
smtp_domain is the
HELO/EHLO domain; i.e. your hostname.
RFC 5321 has this to say about the HELO/EHLO parameter:
o The domain name given in the EHLO command MUST be either a primary host name (a domain name that resolves to an address RR) or, if the host has no name, an address literal, as described in Section 4.1.3 and discussed further in the EHLO discussion of Section 4.1.4.
So, the term
[smtp_]helo_hostname would've been a lot more