DNS Lookup: How to Check DNS Records Online and Troubleshoot Domain Problems

A DNS lookup retrieves the resource records published for a domain or hostname. It helps identify website addresses, email routes, nameservers, aliases, verification tokens, and DNSSEC data.

Check DNS records online with DNSCheckers.com.

What Can a DNS Lookup Answer?

• What IPv4 or IPv6 address does the hostname use?
• Which mail servers receive email?
• Which nameservers are authoritative?
• Does a subdomain use a CNAME?
• Are SPF, DKIM, DMARC, or verification records present?
• Are DS and DNSKEY records published?

Common DNS Record Types

A and AAAA

Map hostnames to IPv4 and IPv6 addresses.

CNAME

Makes one hostname an alias of another hostname.

MX

Identifies incoming mail servers.

TXT

Stores SPF, DKIM, DMARC, and verification data.

NS and SOA

Identify authoritative servers and zone-administration data.

PTR

Maps an IP address back to a hostname.

CAA

Restricts certificate-authority issuance.

SRV

Publishes a service hostname and port.

DS and DNSKEY

Support DNSSEC validation.

How to Perform a DNS Lookup

1. Enter the exact domain or hostname.
2. Select a record type or ALL.
3. Run the lookup.
4. Compare the result with the expected configuration.
5. Check related hostnames separately.
6. Use global propagation testing after recent changes.

Examples of Exact Hostnames

example.com
www.example.com
mail.example.com
selector1._domainkey.example.com
_dmarc.example.com

DNS Lookup vs Propagation Checker

A DNS lookup retrieves records from a selected source. A propagation checker compares the same record across several geographic resolvers.

Use the global checker when different users receive different results.

How to Read Common Responses

Expected Record

DNS is published, but the related application must still be tested.

Old Record

The result may be cached or the wrong DNS zone may have been edited.

NXDOMAIN

The resolver reports that the queried name does not exist.

SERVFAIL

The resolver could not complete the query, possibly because of nameserver or DNSSEC problems.

Command-Line DNS Lookups

nslookup example.com
nslookup -type=MX example.com
dig A example.com
dig TXT example.com
dig NS example.com

Troubleshooting Checklist

1. Confirm the spelling and exact hostname.
2. Check authoritative NS records.
3. Query both A and AAAA.
4. Review TTL values.
5. Compare recursive and authoritative answers.
6. Check global propagation.
7. Verify the destination service.
8. Inspect SSL and firewall settings.

Frequently Asked Questions

Can I check every DNS record at once?

Yes. Use the ALL option in a full DNS lookup tool.

Why do two tools show different answers?

They may use different resolvers, caches, or authoritative-query methods.

Does a DNS lookup change records?

No. It reads published data and does not edit the zone.

Why must I enter the full subdomain?

DNS records belong to exact names. A query for example.com does not automatically query mail.example.com.

Conclusion

DNS lookup is a fundamental diagnostic step for website, email, domain, and security problems.

Use the DNSCheckers.com Full DNS Lookup Tool to retrieve supported record types.