Security Tools

DNS Lookup

Look up A, AAAA, MX, NS, TXT, CNAME and SOA records for any domain.

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About this tool

Look up the public records that tell the internet where a website lives and how its email is handled. Enter a hostname and the tool shows its A, AAAA, MX, NS, TXT, CNAME and SOA records in one place.

How to use it

Enter a hostname such as example.com.
Run the lookup.
Browse the results grouped by record type.

Record types explained

A – the IPv4 address of the server.
AAAA – the IPv6 address, if one is published.
MX – the mail servers that accept email, with their priority.
NS – the nameservers that hold the zone.
TXT – text entries used for SPF, DKIM, DMARC and ownership verification.
CNAME – an alias that points one hostname to another.
SOA – the start-of-authority entry with the primary nameserver and serial number.

When it helps

After moving to a new host, confirm the A record points to the right server. If email stops arriving, check that the MX entries are correct. When a service such as Google Search Console asks you to verify ownership, make sure your TXT entry has been published. Developers also use lookups to debug CDN setups and subdomain aliases.

Why results can change

Records are cached by resolvers around the world for the time set in each entry (TTL). After an update, some locations may show the old values for a few minutes or, occasionally, up to a day or two. A missing record does not always mean something is wrong — for example, many sites simply do not publish IPv6.

Limitations

Only publicly published records are shown. Private or internal zones are not visible, and this is not a full security or server-health audit.

A worked example

A small business moves its website to a new host on Friday. On Monday some customers still see the old site. A lookup shows the A record already points to the new server, but the TTL was set to 24 hours, so a few networks are still using the cached answer. The fix is simply to wait — and next time, lower the TTL a day before migrating.

Email deliverability checklist

An MX record pointing to your mail provider.
An SPF TXT entry listing every service that sends mail for you.
A DKIM entry published by your provider.
A DMARC policy, starting with p=none to monitor before tightening.

Before and after a migration

Note your current records so you can roll back.
Lower the TTL to around five minutes a day in advance.
Make the change and confirm it with a lookup.
Raise the TTL again once everything works.

Reading TXT entries

TXT values can look cryptic, but most follow a recognisable pattern: v=spf1 for SPF, v=DMARC1 for DMARC and long strings beginning with service names for ownership verification. Remove verification strings for services you no longer use to keep the zone tidy.

Related tools

DNS Records Lookup – a second view of the same zone
Whois Checker – see registrar and nameserver details
Email Header Analyzer – check SPF, DKIM and DMARC results on a real message

Glossary

TTL – how long resolvers may cache a record.
Resolver – the server that answers lookups for your device.

Frequently asked questions

A, AAAA, MX, NS, TXT, CNAME and SOA records.

Resolvers cache records for the time set in their TTL, so changes can take from a few minutes to a day to appear everywhere.

They point visitors to your server, route your email and prove ownership to services such as search consoles.

Around an hour is a sensible default; lower it to a few minutes before planned changes.

Look for a TXT entry beginning with v=spf1 in the results.