- Plesk Onyx for Linux
Incoming mail from some domains rejected or quarantined by DMARC
/var/log/mailllogfile contains the error:
CONFIG_TEXT: spf: Error code: (18) Mechanisms used too many DNS lookups
- SPF ships with a built-in limit to the number of "DNS-querying mechanisms" that a set of SPF records can contain. That limit is 10.
- Misconfigured "SPF local rules" in Tools & Settings > Mail Server Settings
Make sure that "SPF local rules" are configured properly
- Login to Plesk
Tools & Settings > Mail Server Settings
and check that "SPF local rules" record does not start with
v=spf1and does not end with something like
If "SPF local rules" are valid, but the issue persists. Then verify all SPF rules by following all "include" directives, if any, for sender domain to make sure that total count of SPF records below does not exceed 10.
Local rules - the rules that are used by the spam filter before the SPF check is actually done by the mail server.
These rules are concatenated with the rules specified in the SPF-related DNS record or the sender. For example, if the sender has the following SPF policy:
example.com TXT v=spf1 +a +mx –all
and the local rule is
, then the resulting policy will be
example.com. TXT v=spf1 +a +mx +a:test.plesk.com –all
This tool might be helpful to validate SPF record: http://www.kitterman.com/spf/validate.html