Don't know who hosts your email?

The fastest way to find out is to run an MX lookup on your domain — the MX records tell you exactly which provider is receiving your mail. Or run the full diagnostic, which auto-detects your mail provider and lists it at the top of the report.

What "setting up email authentication" actually means

Email authentication is three DNS records, all published at your DNS provider, that together prove a message really came from your domain:

• SPF lists which servers may send as you. Every mail provider has a specific include: token you add to your SPF record.
• DKIM cryptographically signs each outgoing message. Your mail provider generates the key pair — you publish the public key in DNS as a TXT or CNAME record.
• DMARC tells receivers what to do when SPF or DKIM fail. The starter record is the same for every provider; you tighten it later.

The provider pages below cover all three. If you don't already know how to add a DNS record, the matching DNS-provider guides walk through that part.