SPF explained
SPF: who may send email as your domain
SPF is a list of the servers allowed to send mail from your domain. Receivers check it on every message.
Where it lives
One TXT record on your root domain.
v=spf1 include:_spf.google.com ~allWhat to know
One record only
A domain must have exactly one SPF record. Two records means both are ignored.
Ten lookups at most
Each include: costs a DNS lookup. Past ten, receivers treat SPF as broken.
~all or -all
~all marks other senders as suspicious; -all rejects them. Start with ~all.
Common mistakes
- Two SPF records after switching email providers
- Adding every tool you ever tried until you pass ten lookups
- Forgetting the sending tool you actually use