# Fix email authentication for vercel.com

You are working on the DNS and mail configuration for vercel.com.
Measured by MailAuthWatch on 17 Oct 2026 from public DNS. Grade A (95/100).
Report: https://www.mailauthwatch.com/check/vercel.com

## What is published right now (do not assume anything else)
- SPF (TXT vercel.com): v=spf1 include:_netblocks.google.com include:_netblocks2.google.com include:_netblocks3.google.com include:mktomail.com include:amazonses.com include:sendgrid.net include:_spf.salesforce.com include:spf.mtasv.net ~all   — valid, 10 of 10 lookups
- DMARC (TXT _dmarc.vercel.com): v=DMARC1; p=quarantine; rua=mailto:df9481016e14030@rep.dmarcanalyzer.com; ruf=mailto:df9481016e14030@for.dmarcanalyzer.com; pct=100; fo=1;
- DKIM: google._domainkey (2048-bit), k1._domainkey (1024-bit), s1._domainkey (2048-bit), s2._domainkey (1024-bit), m1._domainkey (1024-bit)
- MX: aspmx.l.google.com, alt1.aspmx.l.google.com, alt2.aspmx.l.google.com, aspmx2.googlemail.com, aspmx3.googlemail.com  → Google Workspace
- Nameservers: ns1.vercel-dns.com, ns2.vercel-dns.com  → records are managed in Vercel DNS

## Tasks, in order of impact
### 1. 3 DKIM keys are 1024-bit.
Why: Selectors k1._domainkey, s2._domainkey, m1._domainkey are under 2048 bits, which some receivers already downgrade. 
Rotate to a 2048-bit key at the sending service.

### 2. SPF uses 10 of 10 lookups. One more include breaks it.
Why: Nothing is failing yet. This is the warning you want before it does.
Trim an unused include now, or monitor so the next addition is caught the same day.

## 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 Vercel DNS or Google Workspace, stop and say exactly what access you need.

## Verify
  dig +short TXT vercel.com
  dig +short TXT _dmarc.vercel.com
Then open https://www.mailauthwatch.com/check/vercel.com?fresh=1 and confirm:
  the grade is unchanged and no new issues appear. 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.