DNS · Domain · IP · Security Intelligence
Analyse DNS records, nameservers, IPs, SSL, email security, infrastructure and domain configuration from a single lookup.
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Domain • analysed just now
| Type | Name | Value | TTL | Priority | Status |
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Source: Authoritative DNS (queried directly, with resolver fallback)
Choose a record type and click “Check Propagation”.
Every tool operates on your current target automatically — no retyping.
Plain-English explanations for every concept DNSDecode analyses.
The Domain Name System translates human-readable names like example.com into the IP addresses computers use to route traffic. It is effectively the phonebook of the internet, and almost every online interaction begins with a DNS lookup.
A resolver asks a root server which organisation manages a domain's top-level domain (e.g. .com), then asks that TLD server which nameservers are authoritative for the domain itself, and finally asks those nameservers for the actual record. Most of this is cached to keep lookups fast.
An A record maps a hostname directly to an IPv4 address. It is the most fundamental DNS record type — without one, a domain typically cannot be reached over IPv4. Read the full record types guide →
MX (Mail Exchange) records tell the internet which mail servers are responsible for accepting email for a domain, and in what priority order. No MX record generally means no inbound email. Read the full record types guide →
DNSSEC adds cryptographic signatures to DNS responses so resolvers can verify that an answer genuinely came from the domain's authoritative nameservers and was not tampered with in transit. Read the full DNSSEC guide →
Sender Policy Framework lets a domain publish which mail servers are authorised to send email on its behalf. Receiving servers check the sending IP against this list to help detect spoofed mail. Read the full email authentication guide →
DomainKeys Identified Mail attaches a cryptographic signature to outgoing email, letting receivers verify the message was not altered and genuinely originated from an authorised sender for the domain. Read the full email authentication guide →
DMARC builds on SPF and DKIM, telling receiving mail servers what to do when a message fails those checks — monitor only, quarantine, or reject — and provides reporting back to the domain owner. Read the full email authentication guide →
When a DNS record changes, it can take time for that change to be visible everywhere, as resolvers around the world cache the previous answer until its TTL (time-to-live) expires. Checking propagation compares answers from multiple resolvers to see how far a change has spread. Read the full propagation guide →
Reverse DNS (PTR records) maps an IP address back to a hostname — the opposite of a normal lookup. It is commonly used by mail servers to sanity-check that a sending IP has a legitimate, matching hostname. Read the DNS troubleshooting guide →