What is a DNS lookup?
A DNS lookup retrieves Domain Name System records associated with a domain name. DNS records contain information used to direct web traffic, route email, identify authoritative name servers, verify domain ownership and configure many other Internet services.
For example, an A record maps a hostname to an IPv4 address, an AAAA record maps it to an IPv6 address, and an MX record identifies the mail servers responsible for receiving email for a domain.
What is DNS?
DNS stands for Domain Name System. It acts as a distributed naming system that allows people to use domain names instead of remembering numerical IP addresses.
When you enter a domain name into a browser, DNS helps determine which IP address or service the domain should connect to. Different record types provide different pieces of information about the domain.
Common DNS record types
| Record | Purpose |
|---|---|
| A | Maps a domain or hostname to an IPv4 address. |
| AAAA | Maps a domain or hostname to an IPv6 address. |
| MX | Identifies mail servers responsible for receiving email. |
| TXT | Stores text-based information such as SPF, verification and policy data. |
| CNAME | Creates an alias from one hostname to another hostname. |
| NS | Identifies authoritative name servers for a DNS zone. |
| SOA | Contains administrative information about a DNS zone. |
| CAA | Specifies which certificate authorities may issue certificates for a domain. |
How does a DNS lookup work?
The tool sends a DNS query for the selected domain and record type to a DNS resolver. The resolver returns any matching records along with information such as the record value and Time To Live, or TTL.
MK Tech Tools uses DNS over HTTPS for this lookup. DNS over HTTPS carries DNS queries inside encrypted HTTPS connections rather than sending a traditional unencrypted DNS request from the browser.
How to use the DNS lookup
- Enter a domain such as example.com.
- Select the DNS record type you want to check.
- Click Lookup DNS.
- Review the DNS records returned by the resolver and their TTL values.
- Use the Copy button to copy a record value when needed.
What is DNS TTL?
TTL stands for Time To Live. A DNS record's TTL tells recursive resolvers how long they may cache the record before requesting a fresh value.
A shorter TTL can allow DNS changes to be noticed sooner after cached records expire, while longer TTL values can reduce repeated DNS queries. Actual DNS propagation also depends on caching behavior and the previous TTL value.
A record vs AAAA record
An A record points a hostname to an IPv4 address, while an AAAA record points a hostname to an IPv6 address. A domain can have one, both or multiple records depending on how its network services are configured.
What is an MX lookup?
An MX lookup retrieves the mail exchange records for a domain. MX records identify which mail servers should receive messages sent to email addresses at that domain.
MX records normally include a preference value. Lower preference numbers are generally preferred before higher-numbered servers when multiple MX records are present.
What are TXT records used for?
TXT records store text associated with a DNS name. They are widely used for domain verification, email authentication policies such as SPF and other service-specific configuration.
DNS lookup vs DNS propagation
A DNS lookup shows the answer returned by a particular resolver at the time of the query. It does not by itself prove that every resolver around the world currently has the same cached answer.
When DNS records have recently changed, different recursive resolvers may temporarily return different results until their cached records expire and are refreshed.
Frequently asked questions
How do I find the IP address of a domain?
Select the A record type to look for IPv4 addresses or the AAAA record type to look for IPv6 addresses associated with the hostname.
How do I check a domain's MX records?
Select MX from the record type list and run the lookup. The returned records identify the domain's configured mail exchange servers.
How do I check a TXT record?
Select TXT and run the DNS lookup. TXT results may contain domain verification values, SPF policies and other text-based DNS information.
What does it mean if no DNS record is found?
It means the resolver did not return a record of the selected type for that name. The domain may still have other DNS record types.
Can a domain have multiple A or MX records?
Yes. Domains can have multiple records of the same type, for example multiple IP addresses or multiple mail servers.
Does a DNS lookup change any DNS records?
No. A DNS lookup only reads currently available DNS information. It does not make changes to the domain's DNS configuration.