Google and Yahoo tightened bulk sender requirements over the past couple of years, and by now most major inbox providers expect senders to have proper email authentication in place. If you're running an Email Marketing VPS, here's a plain-language breakdown of the three records that matter.
SPF is a DNS record that lists which servers are allowed to send email on behalf of your domain. Without it, receiving mail servers have no way to confirm your VPS is actually authorized to send as you.
DKIM adds a cryptographic signature to outgoing messages, letting the receiving server verify the message wasn't altered in transit and genuinely came from your domain.
DMARC tells receiving servers what to do if a message fails SPF or DKIM checks — reject it, quarantine it, or let it through — and gives you visibility into who's sending mail as your domain.
If you're setting up bulk sending on a VPS, configuring all three correctly — along with a clean sending IP and reasonable send volume ramp-up — has a much bigger effect on deliverability than the sending software you choose. Our Email Marketing VPS plans include dedicated IPs and Port 25 support to make this setup straightforward.
