DNSSEC cryptographically signs DNS records so resolvers can verify they haven't been tampered with in transit — protects against DNS spoofing/cache poisoning that could otherwise undermine SPF/DKIM/DMARC trust at the DNS layer itself.
If DNS itself isn't trustworthy, authentication records sitting on top of it can theoretically be spoofed via DNS attacks. Not universally required but considered best practice for security-mature domains.
DNSSEC enabled at the registrar but not fully chained to the DNS provider (broken validation), or never enabled at all — the most common case industry-wide.
Run a free, instant audit of DNSSEC and every other authentication record on any domain.
Run a Free DNSSEC CheckLike MTA-STS, this is a "does this company actually invest in infra security" signal — useful shorthand in competitive benchmarking content.