# Fix email authentication for facebook.com

You are working on the DNS and mail configuration for facebook.com.
Measured by MailAuthWatch on 17 Oct 2026 from public DNS. Grade B (75/100).
Report: https://www.mailauthwatch.com/check/facebook.com

## What is published right now (do not assume anything else)
- SPF (TXT facebook.com): v=spf1 redirect=_spf.facebook.com   — valid, 1 of 10 lookups
- DMARC (TXT _dmarc.facebook.com): v=DMARC1; p=reject; rua=mailto:a@dmarc.facebookmail.com; pct=100
- DKIM: no key found under 79 common selectors; revoked: default
- MX: smtpin.vvv.facebook.com  → a custom mail host
- Nameservers: c.ns.facebook.com, a.ns.facebook.com …  → DNS host not recognised

## Tasks, in order of impact
### 1. The only DKIM selector found (default) is revoked.
Why: A selector published with an empty key tells receivers to fail any mail signed with it, and no active key was found under common selectors.
Publish a new key under an active selector:
Turn on DKIM signing at the mail provider and at every third-party service that sends as this domain (CRM, newsletter tool, help desk).
Publish the selector records each service shows. If DKIM is already on with a selector not in the common list, add that selector to the MailAuthWatch check instead.

### 2. No DKIM key found under 79 common selectors.
Why: Either DKIM signing is off, or it uses a selector we did not probe. Without DKIM, forwarded mail and anything that breaks SPF fails DMARC.
Turn on DKIM signing at the mail provider and at every third-party service that sends as this domain (CRM, newsletter tool, help desk).
Publish the selector records each service shows. If DKIM is already on with a selector not in the common list, add that selector to the MailAuthWatch check instead.

### 3. Aggregate reports are being sent to a domain that has not authorised yours.
Why: dmarc.facebookmail.com has not published facebook.com._report._dmarc.dmarc.facebookmail.com, so receivers will discard aggregate reports sent there.
Ask the report provider to publish the authorisation record, or use an address on your own domain.

## Rules
- Publish exactly one SPF record; never add a second v=spf1 TXT.
- Do not remove any include: or ip4: you cannot account for; mail may depend on it.
- Do not set DMARC to p=reject in one step; stage through p=none → quarantine → reject.
- Show the planned DNS changes as a diff (record, old value, new value) before applying them.
- If you cannot access the DNS provider, stop and say exactly what access you need.

## Verify
  dig +short TXT facebook.com
  dig +short TXT _dmarc.facebook.com
Then open https://www.mailauthwatch.com/check/facebook.com?fresh=1 and confirm:
  DKIM found. Target grade: A.

## Report back
List each record you changed (name, type, old value, new value), what you verified, and anything you could not do.