ServerLookup

Server Lookup

DNS Record Lookup & Server Analysis

Search any domain or IP to inspect DNS records, providers, and technical signals in seconds.

Try example.com, github.com, 8.8.8.8

New to DNS? Read the DNS record types guide for examples and best practices.

Lookup results will appear here.

Enter a domain or IP above and hit lookup to view DNS, WHOIS, and infrastructure signals.

Examples: example.com, github.com, 8.8.8.8

DNS fundamentals

DNS Record Types Explained

Everything you need to know about DNS record types, explained in plain English. Whether you're setting up your first website or managing enterprise DNS infrastructure, this guide covers all record types with practical examples and common use cases.

Quick jump

A IPv4 addressAAAA IPv6 addressCNAME Canonical nameNS Name serverSOA Start of authority
Showing 5 record types

A

Essential

IPv4 address

A

In plain English

This is like a phone book entry that tells the internet where to find your website using the older IPv4 address format (like 192.168.1.1).

Points a hostname to an IPv4 address. Core record for directing traffic to a server.

Common uses

  • Root domain pointing to a web server (example.com)
  • Multiple A records for simple load balancing
  • Pointing subdomains to different servers

Example

example.com -> 93.184.216.34
TTL: 300-3600 seconds Related: AAAA, CNAME
Common mistakes to avoid
  • Using CNAME at the apex instead of A record
  • Forgetting to update A record after server IP change
  • Setting TTL too high before a planned migration

AAAA

Common

IPv6 address

AAAA

In plain English

The newer version of the A record that uses the modern IPv6 address format (longer addresses like 2001:db8::1). It's becoming increasingly important as the internet runs out of IPv4 addresses.

Maps a hostname to an IPv6 address to serve dual-stack traffic.

Common uses

  • Enable IPv6 delivery alongside A records
  • CDN or edge nodes with IPv6 support
  • Future-proofing your infrastructure

Example

example.com -> 2606:2800:220:1:248:1893:25c8:1946
TTL: 300-3600 seconds Related: A
Common mistakes to avoid
  • Only having IPv6 without IPv4 fallback
  • Inconsistent IPv6 support across subdomains

CNAME

Essential

Canonical name

CNAME

In plain English

Think of this as a nickname or forwarding address. Instead of pointing directly to an IP address, it says "go look up this other domain name instead."

Creates an alias from one hostname to another. The target must be another hostname, not an IP.

Common uses

  • Point www to the apex domain (www.example.com -> example.com)
  • Alias service subdomains to a provider hostname
  • Simplify management by pointing multiple domains to one location

Example

www.example.com -> example.com
Related: A, AAAA, DNAME

Important note

Cannot be used at the zone apex (the root domain). Must use A/AAAA records there.

Common mistakes to avoid
  • Using CNAME at the root domain (violates DNS standards)
  • Creating a CNAME that points to another CNAME (chain)
  • Mixing CNAME with other record types on the same name

NS

Essential

Name server

NS

In plain English

This tells the internet which DNS servers are responsible for answering questions about your domain. Think of it as pointing to the authorities who know all about your domain.

Delegates a zone to authoritative DNS servers. NS records must exist at the apex of the zone.

Common uses

  • Point a domain to a DNS provider (Cloudflare, Route53, etc.)
  • Sub-delegation for child zones
  • Distribute DNS across multiple name servers

Example

ns1.dnshost.com
Related: SOA, A, AAAA

Important note

Keep NS records consistent at your domain registrar and in your DNS zone.

Common mistakes to avoid
  • Mismatched NS records between registrar and DNS zone
  • Not updating NS records when changing DNS providers
  • Using only one name server (no redundancy)

SOA

Essential

Start of authority

SOA

In plain English

The master record that contains administrative information about your DNS zone, including who's in charge, version number, and refresh timing.

Contains zone-wide metadata such as serial number, refresh intervals, and contact email. Every zone must have exactly one SOA record.

Common uses

  • Required baseline record for every DNS zone
  • Tracking zone version changes via serial number
  • Controlling DNS refresh and retry intervals

Example

ns1.example.com admin.example.com 2024010101 7200 3600 1209600 86400
Related: NS
Common mistakes to avoid
  • Not incrementing serial number after zone changes
  • Invalid email address format (should use dot instead of @)

DNS essentials to remember

  • TTL (Time To Live) balances freshness and performance. Use short TTLs (300-600s) during migrations or when expecting changes. Use longer TTLs (3600-86400s) for stable records to reduce DNS query load.
  • IPv4 and IPv6 coexistence: A and AAAA records work together seamlessly. Always test both IPv4 and IPv6 connectivity to ensure all users can reach your services.
  • MX priorities: Lower numbers win. Always maintain at least two MX records with different priorities for redundancy. If one mail server fails, email will automatically route to the backup.
  • Zone apex restriction: CNAMEs cannot exist at the root domain (example.com) - they violate DNS standards. Use A/AAAA records at the apex, or check if your DNS provider offers ALIAS/ANAME records as an alternative.
  • TXT is versatile: This flexible record type handles SPF email authentication, DKIM public keys, DMARC policies, domain verification tokens, and more. Each use case has specific syntax requirements.
  • PTR records for email: These live in the reverse DNS zone controlled by your IP owner (ISP/hosting provider). Setting correct PTR records for mail servers significantly improves email deliverability.
  • DNSSEC adds authenticity: DS records live in the parent zone (registrar), while DNSKEY and RRSIG records live in your DNS zone. Both are needed for the complete chain of trust.

Quick start scenarios

Launching a new website

  • • Add A record for your root domain (example.com) pointing to your server IP
  • • Add AAAA record if your server has IPv6
  • • Add CNAME for www pointing to your root domain
  • • Your DNS provider automatically creates NS and SOA records
  • • Consider adding CAA to control certificate issuance

Setting up email

  • • Add MX records pointing to your mail servers (with priorities)
  • • Create SPF record (TXT) listing authorized mail servers
  • • Add DKIM record (TXT) with your public key
  • • Set DMARC policy (TXT) for handling failed authentication
  • • Ensure PTR records are set by your hosting provider

Improving security

  • • Add CAA record to control which CAs can issue certificates
  • • Enable DNSSEC with DS + DNSKEY records
  • • Consider TLSA records for DANE certificate pinning
  • • Add SSHFP records to publish SSH host key fingerprints
  • • Review all TXT records for proper SPF/DMARC configuration

Advanced service setup

  • • Use SRV records for service discovery (SIP, XMPP, etc.)
  • • Add HTTPS/SVCB records for modern connection optimization
  • • Configure NAPTR records for telecom applications
  • • Set LOC records if geographic location is relevant

Frequently asked questions

How long does it take for DNS changes to propagate?

DNS propagation depends on the TTL (Time To Live) value of your records. If your old TTL was 3600 seconds (1 hour), it can take up to that long for all DNS servers worldwide to refresh their cache. To speed up future changes, lower your TTL to 300-600 seconds a day before making changes, then raise it again after propagation is complete. Full global propagation typically takes 24-48 hours in the worst case.

What's the difference between A and CNAME records?

An A record points directly to an IP address (like 192.0.2.1), while a CNAME points to another hostname (like example.com). Think of A records as final destinations and CNAMEs as forwarding addresses. Use A records when you know the IP address, and CNAMEs when you want to alias one hostname to another. Remember: CNAMEs cannot be used at the root domain and cannot coexist with other record types on the same name.

Do I need DNSSEC for my website?

DNSSEC adds cryptographic signatures to your DNS records, preventing DNS spoofing and cache poisoning attacks. While not mandatory, it's increasingly important for security-conscious organizations, financial services, government sites, and any service handling sensitive data. The main downsides are added complexity and the need to carefully manage key rotation. If you're just starting out, focus on getting basic DNS right first, then consider DNSSEC as your infrastructure matures.

Why is my email going to spam?

Email deliverability depends heavily on proper DNS configuration. Ensure you have: (1) SPF record listing all authorized mail servers, (2) DKIM record with your public key for email signing, (3) DMARC policy telling receivers what to do with failed authentication, (4) Correct PTR (reverse DNS) records set by your hosting provider, and (5) MX records pointing to valid mail servers. Missing or misconfigured any of these can trigger spam filters.

Can I have multiple A records for load balancing?

Yes, you can add multiple A records for the same hostname, and DNS will return all of them. Clients typically pick one randomly (DNS round-robin). However, this is a very basic form of load balancing with limitations: no health checking, no geographic routing, and uneven distribution. For production load balancing, consider using a proper load balancer service or CDN like Cloudflare, AWS ELB, or similar. These services use Anycast and provide intelligent routing, health checks, and geographic distribution.

Ready to look up DNS records?

Server Lookup provides instant DNS queries, IP geolocation, and network infrastructure inspection for any domain. Query live DNS records, check propagation across global resolvers, and analyze hosting details—all powered by modern, open-source tools.

Check DNS propagation Server Lookup WHOIS Lookup

Common DNS terms explained

TTL (Time To Live)

How long (in seconds) DNS servers should cache a record before checking for updates. Lower = fresher data but more queries. Higher = less traffic but slower updates.

Zone Apex / Root Domain

The base domain without any subdomain (example.com, not www.example.com). Has special DNS rules—like no CNAME allowed.

Authoritative DNS Server

The DNS server that holds the actual, original records for a domain. It's the source of truth, not a cached copy.

Recursive DNS Resolver

The DNS server your device asks when looking up a domain. It queries authoritative servers on your behalf and caches results (like Google DNS 8.8.8.8 or Cloudflare 1.1.1.1).

DNS Propagation

The time it takes for DNS changes to spread across all DNS servers worldwide. Depends on TTL and caching behavior.

Subdomain

A domain that's part of a larger domain, like www.example.com or mail.example.com. Each can have its own DNS records.

DNS Zone

A portion of the DNS namespace managed by a specific organization or administrator. Contains all DNS records for that domain.

Wildcard Record

A DNS record using an asterisk (*) that matches any subdomain not explicitly defined. For example, *.example.com matches any.example.com.

What is Server Lookup?

Server lookup helps engineers debug DNS issues, verify hosting providers, and validate security posture across domains and IPs.

  • Confirm A/AAAA records, MX setup, TXT policies, and NS delegation health
  • Spot CDN or proxy layers, stale DNS, and migration gaps before they ship
  • Audit SPF/DMARC alignment and third-party service connections on a domain

Use it as a fast pre-flight check when launching services or investigating delivery, routing, or availability anomalies.