Modern mailbox providers (Google, Yahoo, Microsoft) enforce mandatory email authentication standards. Senders without valid SPF, DKIM, and strict DMARC policies face immediate spam filtering or hard rejection.
1. Core DNS Authentication Records
🔒 Authoritative DNS Configuration Blueprint
# SPF Record (Flattened < 10 Lookups)
v=spf1 ip4:192.0.2.1/24 include:_spf.mailcampaign.us -all
# DKIM Record (2048-Bit RSA Key Selector)
s1._domainkey.mailcampaign.us. IN TXT "v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA..."
# DMARC Policy (Full Rejection & RUA Aggregate Telemetry)
_dmarc.mailcampaign.us. IN TXT "v=DMARC1; p=reject; sp=reject; pct=100; rua=mailto:dmarc-rua@mailcampaign.us; ruf=mailto:dmarc-ruf@mailcampaign.us; fo=1;"