[ Free tool · DNS & Mail Servers ]
NameServer Checker
List a domain's nameservers and catch lame or single-point-of-failure DNS.
[ About this tool ]
This NameServer checker lists a domain's authoritative NS records, resolves every nameserver to its IPv4 and IPv6 addresses, reads the SOA and flags lame delegation or missing redundancy.
How to read the results
- ›You need at least two nameservers, ideally on different networks.
- ›A nameserver with no address is a lame delegation and causes lookup failures.
- ›Using a second DNS provider protects SPF, DKIM and DMARC lookups during outages.
Frequently asked questions
Why do nameservers matter for email authentication?
Receivers look up your SPF, DKIM and DMARC records through your nameservers. If they fail, those checks return temperror and mail can be deferred or rejected.
How many nameservers should a domain have?
At least two, as required by RFC 1034. Most providers give four, spread across separate networks.
Learn more in our guide: Email Security: Stop Spoofing, Phishing and BEC
Enterprise provenance
Why top financial institutions and governments retired their email security dashboards.
Traditional email authentication platforms sell you a dashboard and ask your engineers to do the labour. In high-stakes environments, manual oversight means delayed enforcement, configuration drift and unmonitored shadow domains.
EmailAuth is the agentic email provenance platform. Our agents enforce p=reject, keep third-party senders aligned and move your domains to full RFC 9989 compliance, the new DMARC standard,, with human-in-the-loop auditability.
SaaS · Dedicated tenancy · Air-gapped on-prem · BYOK encryption
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