Definition
Sender Policy Framework (SPF) allows domain owners to specify which mail servers are permitted to send email on their behalf. Receiving servers check the SPF record to verify that incoming mail comes from an authorised source. Mail from unauthorised servers may be rejected or marked as spam.
Record Format
An SPF record is a TXT record published at your domain root. A typical record looks like:
v=spf1 include:_spf.your-esp.com include:mail.yourdomain.com ~all
Key Components
v=spf1: Version identifier — always requiredinclude:: Authorises another domain's SPF record (used for ESPs)ip4:andip6:: Authorises specific IP addresses or rangesa:andmx: Authorises your domain's A and MX records~all: Soft fail — mail from unauthorised servers is marked but not rejected-all: Hard fail — mail from unauthorised servers is rejected
Common Mistakes
Exceeding the 10-DNS-lookup limit (SPF has a hard limit of 10 lookups per evaluation). Having multiple SPF records (only one is allowed — the rest are ignored). Forgetting to include your ESP's sending infrastructure.
Related Glossary Terms
AOL Mail for Email Marketers
AOL Mail is a legacy email provider with specific deliverability requirements and rendering quirks, now operating as part of the Yahoo+AOL network under shared infrastructure.
BIMI
BIMI (Brand Indicators for Message Identification) is an email standard that allows brands to display their logo next to their emails in supported email clients. It requires DMARC enforcement at quarantine or reject policy.
Bounce Rate Threshold
A bounce rate threshold is the percentage of hard or soft bounces at which email platforms and ISPs begin to penalise sender reputation, typically around 2-5%.
Bounce Rate
Email bounce rate is the percentage of emails that were rejected by the receiving server before reaching the recipient. It is a key indicator of list health and data quality.
Email Deliverability
Email deliverability is the ability to land in the recipient's inbox rather than the spam folder. It depends on sender reputation, authentication, list quality, and content practices.
DKIM (DomainKeys Identified Mail)
DKIM (DomainKeys Identified Mail) is an email authentication method that uses digital signatures to verify that an email was not tampered with during transit and comes from a authorised domain.