SPF Void Lookup
Learn what SPF void lookups are, how they can break authentication, and how DMARCeye helps detect and prevent void lookup errors in DNS.
What is an SPF Void Lookup?
An SPF void lookup occurs when a mail server queries a Sender Policy Framework (SPF) record and receives no DNS response or an empty result. These void responses happen when the referenced domain does not exist or has no DNS records of the requested type, such as an A or MX record. Excessive void lookups can lead to SPF evaluation failure.
The SPF standard limits the number of DNS lookups to 10 per evaluation, and also sets a limit of two “void lookups.” If more than two void lookups occur during SPF processing, the result is a “permerror” (permanent error), causing the SPF check to fail even if the message originates from an authorized source.
How SPF Void Lookups Happen
SPF void lookups typically occur when:
- An
include:mechanism references a non-existent domain - A DNS zone is missing required A or MX records
- Third-party senders remove or rename their SPF entries
- A domain in the SPF chain expires or becomes inactive
Example of an SPF record that could trigger a void lookup:
v=spf1 include:_spf.invaliddomain.com -allRisks and Prevention
Excessive void lookups reduce reliability and may cause legitimate mail to fail SPF validation. To prevent this:
- Regularly audit included domains for validity
- Remove outdated or unnecessary includes
- Use SPF flattening to minimize lookups
- Monitor DMARC reports for SPF permerrors
SPF Void Lookup and DMARCeye
DMARCeye uses AI-based technology and smart programming to detect and flag SPF void lookups within your domain’s authentication data. Its DNS validation engine identifies missing or invalid references before they cause failures, helping you optimize SPF records for stability and compliance.
By proactively detecting void lookups, DMARCeye ensures that your SPF configuration remains reliable and that mail authentication continues without interruption. Get full visibility into who is using your domain to send what to whom.
Sign up for a free trial of DMARCeye today and secure your email domain.
To learn more about DMARC and DMARC-related terms, explore the DMARCeye Glossary.