Here's a two-minute test almost no founder has run
For most companies, the honest answer is yes. Not because of a vulnerability someone has to hack — because of a setting nobody ever finished configuring.
The three records nobody explains well
Every domain can publish three DNS records that tell the internet who's allowed to send email on its behalf: SPF, DKIM, and DMARC. In plain terms:
SPF is a list: "these servers are allowed to send mail as my domain."
DKIM is a signature: each email gets cryptographically signed, so the receiving server can confirm it wasn't altered in transit.
DMARC is the enforcement layer: it tells receiving servers what to actually do when a message fails those checks — deliver it anyway, quarantine it, or reject it outright.
That last one is where almost everyone stops halfway. Publishing a DMARC record is easy. Setting it to actually block failing mail is the part most companies skip, often without realizing they skipped it.
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