On Thu, Apr 14, 2022 at 12:25:11AM -0400, Greg Klanderman wrote:
> > This is naturally documented in access(5), and also in postconf(5)
> > under:
> >
> > smtpd_null_access_lookup_key (default: <>)
> > The lookup key to be used in SMTP access(5) tables instead of the
> > null sender address.
>
> Thank you Viktor, I had searched access(5) for 'blank' and 'empty' but
> not 'null'.
Sadly nobody *reads* documentation these days, all we seem to know how
to do is *search*. The access(5) document is logically organised, and
the text in question is logically located under:
EMAIL ADDRESS PATTERNS
With lookups from indexed files such as DB or DBM, or from networked
tables such as NIS, LDAP or SQL, patterns are tried in the order as
listed below:
user@domain
Matches the specified mail address.
domain.tld
Matches domain.tld as the domain part of an email address.
The pattern domain.tld also matches subdomains, but only when
the string smtpd_access_maps is listed in the Postfix par-
ent_domain_matches_subdomains configuration setting.
.domain.tld
Matches subdomains of domain.tld, but only when the string
smtpd_access_maps is not listed in the Postfix par-
ent_domain_matches_subdomains configuration setting.
user@ Matches all mail addresses with the specified user part.
Note: lookup of the null sender address is not possible with some types
of lookup table. By default, Postfix uses <> as the lookup key for such
addresses. The value is specified with the smtpd_null_access_lookup_key
parameter in the Postfix main.cf file.
In other words, looking at the topics covered and then reading the text
under the most relevant topic, rather than searching for a specific
keyword, would have quickly found the answer. Sadly, we're losing the
skill to read more than a snippet found via keyword search. :-(
--
Viktor.
