DKIM fix
DKIM Selectors — What They Are and How to Set Them
The selector tells receivers which TXT row holds the public key. It appears in the DKIM-Signature header as s=[selector] and must match a DNS TXT record at [selector]._domainkey.yourdomain.com.
How selectors work
Receivers read d= and s=, then query s._domainkey.d for the key. More vocabulary in DKIM.
Common selectors by provider
- Google Workspace:
google— setup - SendGrid:
s1,s2— setup - Microsoft 365:
selector1,selector2— setup
Multiple selectors
You can publish several keys (rotation, different services). Each has its own selector._domainkey name. Subdomains need their own records — see subdomain DKIM.
Steps
DKIM-Signature s= and d=s._domainkey.dv=DKIM1; k=rsa; p=... TXT your provider gives youResolve selector DNS
Open DNS Preflight →FAQ
What selector should I use?
Follow your provider's documentation — do not invent arbitrary selectors unless you control signing.
Common provider selectors?
See the list above; each guide links to exact DNS patterns.
Multiple selectors?
Yes — useful for rotation and multi-service setups.
How do I see which selector is used?
Open raw headers and find s= in DKIM-Signature.
Adding a new selector?
Publish new TXT first, switch signing, then retire old keys after overlap.