# SPF +all milter

## Overview

Fight with spam is a long time battle... very old.

Once SPF mechanism allows to fight spam rather efficiently,
some of DNS administrators do not care of SPF records in their
domains and inflict harm to SPF-based spam-filters, adding
substring "+all" to the resource records.

According to its own site, http://www.openspf.org/SPF_Record_Syntax
SPF founders seems to be rather hostile to the aministrators mentioned.

The "SPF +all milter" is a mail filter (milter) to reject all the
mails, sent from domains, which SPF resource records contain
"+all". Almost all of the mail from these domains IS spam.

In rare cases, if your responent should send to you email from such
SPF-careless domain, he whould be notified about the error. Hope, this
should help him to understand the problem and fix the resource
records.

The ordinal sendmail for the mail is the following:

    2015-06-01T07:37:50.956466+03:00 omega sendmail[23216]: t514bnBT023216: Milter: from=<email@domrabota-doma.ru>, reject=530 5.7.1 Sender domain has wrong SPF record (containing +all)
    2015-06-01T07:37:51.008575+03:00 omega sendmail[23216]: t514bnBT023216: from=<email@domrabota-doma.ru>, size=41699, class=0, nrcpts=0, proto=ESMTP, daemon=MTA, relay=[77.221.144.211]

## Running the milter

Milter comunicates to sendmail server though Berkley sockets.
The socket is specified as a single parameter of the binary

    spf-all-milter /var/run/spf-all-milter/milter.sock

Milter does not require root privileges, so you are encouraged to
run it under a separate user account. That's why the directory
where socket is aimed should be created before milter launch and
milter's account should have access to create socket there.

Please, refer to file spf-all-milter.service as an example of
systemd configuration to launch the milter.

Also, create empty file /etc/spf-all-milter-exclusions.conf before
milter launch. Milter should have read access to the file

    touch /etc/spf-all-milter-exclusions.conf

## Exclusions

Also, you can disable the check for the specific domains, using the
exclusions file (/etc/spf-all-milter-exclusions.conf). Just post one
domain name per line.

Exclusions disable checks for the domain at all.

Exclusions disable checks for the certain domain, not its subdomains