You've just transferred a domain, pointed it to a new web host, or set up a custom email domain. You wait. You refresh the page. Nothing happens. Is DNS propagating? Did you enter the records correctly? Is something broken?
This is one of the most frustrating experiences in web development and system administration — and it happens because most people don't fully understand how DNS works or how to check it.
This guide explains DNS from the ground up, walks through every common record type, and shows you how to diagnose propagation and configuration issues quickly.
What is DNS?
DNS stands for Domain Name System. It's the internet's phone book — it translates human-readable domain names like fluxapps.net into the IP addresses computers actually use to connect to each other.
When you type a URL into a browser:
- Your device asks a DNS resolver (usually provided by your ISP or a service like
8.8.8.8) for the IP address of that domain. - The resolver checks its cache. If it has the answer, it returns it immediately.
- If not, it queries the authoritative nameservers for that domain.
- The nameservers return the record, the resolver caches it, and your browser connects.
The entire process typically takes milliseconds. But when you change DNS records, the old answers are cached across thousands of resolvers worldwide — and those caches take time to expire. This is DNS propagation, and it's why changes don't always appear instantly.
Check DNS Records for Any Domain
DNS Lookup
Check DNS records (A, MX, CNAME, TXT) for any host.
The DNS Record Types You'll Actually Encounter
A Record
Maps a domain name to an IPv4 address. This is the most fundamental record — it's what tells browsers where to find your website.
fluxapps.net A 104.21.45.67
AAAA Record
Same as an A record, but for IPv6 addresses (the newer, longer format).
fluxapps.net AAAA 2606:4700:3035::6815:2d43
CNAME Record
A Canonical Name record — it points one domain name to another domain name (not an IP address). Used for subdomains and aliases.
www.fluxapps.net CNAME fluxapps.net
You can't use a CNAME for a root domain (@ / bare domain). Use an A record or a host provider's ALIAS/ANAME record there instead.
MX Record
Mail Exchanger — tells the internet which server handles email for your domain. You'll see these when setting up custom email addresses.
fluxapps.net MX 10 mail.google.com
The number (10) is priority — lower numbers are preferred. If you have multiple mail servers, you'd set different priorities for failover.
TXT Record
A text record with no fixed format — used for verification and security configurations:
- SPF (Sender Policy Framework) — specifies which servers are allowed to send email for your domain
- DKIM — a cryptographic key used to sign outgoing email
- Domain verification — Google Search Console, Stripe, GitHub, and many others ask you to add a TXT record to verify domain ownership
NS Record
Name Server — identifies which DNS servers are authoritative for your domain. When you buy a domain and point it to a new web host, you often update these.
SOA Record
Start of Authority — technical metadata about the DNS zone: which server is primary, when the zone was last updated, and how long records should be cached.
DNS Propagation: Why Changes Take Time
When you update a DNS record, the change doesn't appear everywhere instantly. Every DNS resolver on the internet has cached your old record for a duration called the TTL (Time to Live) — measured in seconds.
Common TTL values:
300= 5 minutes (fast propagation, more DNS traffic)3600= 1 hour (typical)86400= 24 hours (slow to propagate, less traffic)
Best practice before making changes: If you know you're about to change DNS records, lower the TTL to 300 a day before. This way, when you make the change, the old records expire in 5 minutes rather than 24 hours.
After making changes, it typically takes a few minutes to a few hours for most of the world to see the updated records. Some regions or ISPs with aggressive caching may take longer.
Related: Check Domain Registration Details
DNS records tell you how a domain is configured technically. WHOIS records tell you who owns it and when it expires. If you're investigating a domain or troubleshooting ownership issues, check both.
WHOIS Lookup
Look up domain registration details, ownership info, expiry dates, nameservers, and registrar data for any domain name instantly.
Privacy and DNS Research
DNS lookups are often used to research competitors, investigate suspicious traffic sources, or map out a target infrastructure. The tools you use for this research can themselves be a privacy concern:
- For security researchers: IP addresses and domain configurations are sensitive. Cloud-based DNS lookup tools may log your queries, revealing what you're investigating.
- In regulated enterprises (EU GDPR, US HIPAA): DNS configurations of internal systems and customer infrastructure are often confidential. Running lookups through external logging services may violate data governance policies.
- For domain investors: Researching prospective domain acquisitions through tools that log queries can tip off competitors or brokers.
FluxToolkit's DNS Lookup queries public DNS records and runs in your browser — your search queries are not logged or stored.
Frequently Asked Questions
How long does DNS propagation take?
It depends on the TTL of the record being changed. Low TTLs (300 seconds) propagate in minutes. High TTLs (86400 seconds) can take up to 24 hours to fully propagate globally.
Why do I see the old website even after updating DNS?
Your browser and ISP's DNS resolver are likely still serving the cached old record. Try clearing your browser cache, flushing your local DNS cache (ipconfig /flushdns on Windows, sudo dscacheutil -flushcache on macOS), or using a different DNS server (like 8.8.8.8) to test.
What's the difference between A and CNAME records?
An A record maps a name directly to an IP address. A CNAME maps a name to another name — the final resolution still ends in an IP address, but through an intermediate step. CNAMEs are useful for subdomains and aliases but can't be used at the root domain level.
How do I set up email for my domain?
You need two things: MX records pointing to your email provider's mail servers, and TXT records for SPF and DKIM authentication. Your email provider will give you the exact values to add.
Does FluxToolkit store my DNS lookup queries?
No. Lookups are performed directly from your browser and we don't log which domains you search.
Related Articles
WHOIS Lookup Explained: How to Find Out Who Owns a Domain — Pair DNS records with ownership data for a full domain investigation.
Robots.txt Explained: How to Create One — Verify DNS is resolving correctly before configuring crawler access.
Meta Tags Explained: Title Tags and Meta Descriptions — Once your domain is resolving, optimize how it appears in search results.
IP Address Lookup Guide — Find the IP address behind the DNS records you looked up.
Domain Age Checker Guide — Check domain age alongside DNS configuration.
XML Sitemap Generator Guide — Submit your sitemap once DNS is resolving correctly.