The nslookup (Name Server Lookup) command is a simple tool for querying DNS servers on Linux. It is a quick way to check what a domain resolves to, inspect DNS records, and troubleshoot name resolution problems.
If you read my previous post, Linux dig Command: 5 Examples Every Developer Should Know, you'll notice nslookup does similar work with a shorter, friendlier output.
1. Install nslookup
nslookup ships in the same package as dig. On Debian/Ubuntu:
sudo apt update
sudo apt install dnsutils
2. Find a Domain's IP Address
nslookup google.com
The output shows the DNS server that answered your query, followed by the IP addresses for the domain.
Note: If you see
Non-authoritative answer, it means the response came from a cache (such as your ISP's or a public resolver) rather than directly from the domain's own name servers. This is normal.
3. Check Specific DNS Records
Use the -type option to choose a record type:
nslookup -type=A google.com
nslookup -type=AAAA google.com
nslookup -type=MX google.com
nslookup -type=NS google.com
nslookup -type=TXT google.com
| Record | Purpose |
|---|---|
A |
IPv4 address |
AAAA |
IPv6 address |
MX |
Mail servers |
NS |
Name servers |
TXT |
Text records (SPF, domain verification, etc.) |
4. Query a Specific DNS Server
Add the DNS server address at the end of the command:
nslookup google.com 8.8.8.8
This asks Google's public DNS resolver instead of your system default. It's useful for checking whether a problem is caused by your local resolver or by the domain's DNS records.
5. Reverse DNS Lookup
Give nslookup an IP address to find the hostname linked to it:
nslookup 8.8.8.8
Reverse lookups are handy when checking server logs or confirming that an IP address maps back to the expected hostname.
Bonus: Interactive Mode
Run nslookup with no arguments to enter interactive mode:
nslookup
> set type=MX
> google.com
> server 1.1.1.1
> google.com
> exit
This lets you run several queries in a row and change the record type or DNS server between them.
dig vs nslookup
dig |
nslookup |
|
|---|---|---|
| Output | Detailed, script-friendly | Short and simple |
| Trace resolution | Yes (+trace) |
No |
| Best for | In-depth DNS debugging | Quick lookups |
Conclusion
The nslookup command is a fast way to check DNS records and confirm how a domain resolves. Use it for quick checks, and reach for dig when you need more detail.
Next: Linux ping Command: Simple Examples.
About Me
I'm Safal Bhattarai, a Tech Lead, Full Stack Developer, and DevOps Engineer.
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