Tool
DNS Lookup
Query DNS records for any domain — A, AAAA, MX, TXT, NS, CNAME, and more.
About
What is DNS?
The Domain Name System (DNS) is the internet's distributed naming infrastructure, translating human-readable domain names like example.com into the IP addresses that computers use to route traffic. Every time you load a website, send an email, or connect to an API, a DNS query is happening behind the scenes.
DNS is hierarchical and distributed across thousands of authoritative nameservers worldwide. Understanding DNS records is essential for network engineers, system administrators, and security professionals who manage domains, configure mail delivery, implement zero-trust architectures, or investigate phishing infrastructure.
This tool queries DNS records in real time, letting you inspect the authoritative data for any domain without installing command-line utilities like dig or nslookup.
Reference
DNS Record Types Explained
Each DNS record type serves a distinct purpose. Here is a quick reference to the most important record types you will encounter.
A
Maps a domain to an IPv4 address. The most fundamental DNS record.
AAAA
Maps a domain to an IPv6 address for next-generation internet routing.
MX
Specifies mail exchange servers responsible for accepting email for the domain.
TXT
Stores arbitrary text, commonly used for domain verification, SPF, and DMARC policies.
NS
Identifies the authoritative nameservers that hold the DNS records for the domain.
CNAME
Creates an alias from one domain name to another, used for subdomains and CDN routing.
Email Security
Email Security Records
Three TXT-based DNS standards work together to prevent email spoofing and phishing. Checking these records is a core part of email deliverability audits and security assessments.
SPF — Sender Policy Framework
Published as a TXT record, SPF lists the IP addresses and mail servers authorized to send email on behalf of a domain. Receiving servers reject or flag messages from unlisted sources, reducing spoofed email delivery.
DMARC — Domain-based Message Authentication, Reporting & Conformance
DMARC builds on SPF and DKIM by letting domain owners define a policy (none, quarantine, or reject) for messages that fail authentication checks, and receive aggregate reports on email traffic.
DKIM — DomainKeys Identified Mail
DKIM signs outgoing messages with a private key and publishes the corresponding public key in DNS. Recipients verify the signature to confirm the message was not tampered with in transit.
FAQ
Frequently Asked Questions
What is a DNS lookup?+
A DNS lookup queries the Domain Name System to retrieve records associated with a domain — including IP addresses (A/AAAA), mail servers (MX), name servers (NS), text records (TXT), and more.
How do I check MX records for email delivery?+
Select MX from the record type dropdown and enter your domain. Results show all mail exchange servers and their priority values. Lower priority numbers are tried first — a backup server typically has a higher number like 20 or 30.
How do I check SPF, DKIM, and DMARC records?+
SPF and DMARC are TXT records. Query TXT for your domain to find the SPF policy. For DMARC, query _dmarc.yourdomain.com. DKIM public keys are at selector._domainkey.yourdomain.com. CyrusX surfaces all three automatically.
Why do DNS changes take time to propagate?+
DNS records are cached according to their TTL (Time To Live) value. Until the cache expires, resolvers serve the old record. Lowering TTL before a planned change — to 300 seconds — speeds propagation to under 5 minutes.
What is the difference between A and AAAA records?+
An A record maps a domain to an IPv4 address. An AAAA record maps a domain to an IPv6 address. Modern sites typically publish both so clients using either protocol can connect.
What does a CNAME record do?+
A CNAME (Canonical Name) record creates an alias from one domain to another. For example, www.example.com might CNAME to example.com. Note: CNAMEs cannot coexist with other record types at the same name, which is why apex domains (example.com) use A records instead.