How does DNS relate to email?
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When you hit send, your email doesn't just travel directly to the recipient's inbox. It has to find its way there. DNS is the system that makes that possible. Without it, email servers wouldn't know where to look, what to trust, or who's actually allowed to send on your behalf.
Here's what DNS is actually doing for email behind the scenes.
Routing the mail: MX records tell the sending server where to deliver email for your domain. When someone sends to captain@deepcurrent.io, the sending server checks DNS for deepcurrent.io's MX records to find the right mail server. No MX record, no delivery.
Proving you're legitimate: This is where SPF, DKIM, and DMARC come in. All three live in DNS as TXT records. SPF lists the servers that are allowed to send email for your domain. DKIM stores a public key that receiving servers use to verify your message wasn't tampered with in transit. DMARC tells receivers what to do if either check fails. Together, they're how you prove your email is real.
Connecting names to addresses: A records (and their IPv6 equivalent, AAAA records) map your domain name to an IP address. Your mail server needs this to function. Think of it as the street address behind the name.
Reverse verification: PTR records work the other way. They confirm that the IP address sending your mail actually belongs to the hostname it claims. Many receiving mail servers check this as a basic spam filter. If it doesn't match, they get suspicious (fairly).
So if any of these records are wrong or missing, things break. Mail bounces because no MX record exists. Authentication fails because your SPF record lists the wrong servers. Spam filters flag you because your PTR record doesn't line up. DNS isn't just infrastructure, it's the reputation layer your email identity is built on.
If you're not sure your DNS records are set up correctly, you can check your SPF in seconds with our free SPF checker. Or if something feels broken and you're not sure where to start, drop us a message and we'll take a look.
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