DNS Check
Comprehensive DNS lookup and analysis tool for domain troubleshooting
DNS Check Tool Features:
- Multiple Record Types: A, AAAA, MX, TXT, CNAME, NS, SOA
- Full Analysis: Comprehensive DNS analysis with multiple record types
- Reverse DNS: PTR lookups for IP addresses (IPv4 and IPv6)
- Bulk Processing: Check up to 50 domains simultaneously
- Performance Metrics: Response time measurement for all lookups
About the DNS Check Tool
DNS is the directory that maps human-readable domain names onto the addresses and services behind them. When a website will not load, mail bounces, or a certificate fails to validate, the cause is very often a DNS record that is missing, wrong, or still propagating.
This tool queries ten record types — A, AAAA, MX, TXT, CNAME, NS, SOA, PTR, SRV and CAA — either individually or as a full analysis of a domain, plus reverse lookups from an IP address and bulk checks across many domains.
How to use it
- 1Enter a domain name, or switch to reverse lookup and enter an IP address.
- 2Pick a single record type for a targeted check, or run the full analysis to query the standard set at once.
- 3Read the results. Empty answers are meaningful: a domain with no MX record cannot receive mail, and a missing CAA record means any certificate authority may issue for it.
- 4Use bulk mode when you need to check several domains, for example during a migration.
When you would use it
- Confirming what a domain resolves to after moving hosting or changing provider.
- Checking that MX records point where your email provider says they should.
- Diagnosing a subdomain that will not resolve — a missing CNAME, or an A record aimed at the wrong address.
- Auditing a batch of domains at once after a migration.
How it works, and what it does not do
Lookups are performed server-side against the public resolvers the server is configured to use, for whichever record type you choose. Because the query leaves from our server rather than your browser, what you see is that resolver’s answer, which is exactly what you want when hunting a stale record — your own machine may still be serving you a cached copy.
Two limitations are worth stating plainly. First, this is one resolver’s view rather than the whole internet’s: a record can be right here and still be cached incorrectly elsewhere until its TTL expires. Second, successful lookups are cached briefly on our side so that repeated checks stay fast, and each response states whether it came from that cache — so if you are specifically watching for a change to appear, allow a minute between checks.
Frequently asked questions
I changed a record — why do I still see the old value?
DNS answers are cached for the duration of the record's TTL, both by the resolver you are querying and at other layers. The old value will persist until that TTL expires, which is why lowering the TTL before a planned migration is standard practice.
What is the difference between an A and a CNAME record?
An A record maps a name directly to an IPv4 address (AAAA does the same for IPv6). A CNAME says "this name is an alias for that name" and is resolved by following the chain. A CNAME cannot coexist with other records on the same name, which is why the bare domain usually uses an A record.
Why does my TXT record match more than expected?
TXT records are used for several purposes at once — SPF, DKIM, domain verification and others — so a single name often holds multiple TXT entries. The tool returns each one separately rather than concatenating them.
Where are the lookups performed from?
From our servers. That means the result reflects what a resolver in our network sees, which may differ from what a resolver near you sees — DNS answers can legitimately vary by location for load balancing and content delivery.
How long do DNS changes take to show up?
As long as the previous record’s TTL, which is set by whoever controls the zone and is commonly anywhere from five minutes to 24 hours. Lowering the TTL well before a planned migration is what makes the switch appear quickly.
A lookup fails for a domain that definitely exists.
That usually means the specific record type is absent rather than the domain being broken — plenty of domains have no AAAA, TXT or CAA record at all. The response distinguishes “no records of this type” from a resolver failure, so the two cases can be told apart.