SPF void lookups: how to fix them

What it means

While checking SPF, a receiver looks up the names in the record: included domains, the domain's own A and MX records, and so on. A lookup that returns no answer at all, either because the name doesn't exist or because it has no records of that type, is a void lookup. RFC 7208, section 4.6.4 says receivers should allow no more than two. We found more than two in this domain's record, so receivers that apply the limit return a permanent error and SPF fails for every message.

The limit exists because a record full of names that don't resolve is a cheap way to make other people's servers do pointless DNS work.

What causes it

include:

A service you stopped using deleted its SPF record, or renamed it.

a

The domain, or the name after a:, has no A or AAAA record (common on email-only domains).

mx

The domain has no MX records, so mx finds nothing.

typos

A misspelt include, such as _spf.gogle.com, never resolves.

Fixing it

1. Note each term the check lists as returning nothing.
2. Delete includes for services the domain no longer uses. Correct any that are misspelt against the provider's current set-up page.
3. Remove a or mx if the domain has no website address or mail servers of its own, or if those servers don't send email.
4. Check the domain again; the error clears as soon as the count is two or fewer.