How to Use nslookup Command in Linux: Syntax and Examples
The
nslookup command in Linux is used to query DNS servers to find domain name or IP address information. You run nslookup [domain] to get the IP address of a domain or nslookup [IP] to find the domain name. It helps troubleshoot DNS and network issues easily.Syntax
The basic syntax of the nslookup command is:
nslookup [options] [domain-name | IP-address]
Here:
- domain-name: The website or host name you want to look up.
- IP-address: The IP address to find the domain name for (reverse lookup).
- options: Optional flags to customize the query (like specifying DNS server).
bash
nslookup [options] [domain-name | IP-address]
Example
This example shows how to find the IP address of example.com using nslookup. It also shows how to do a reverse lookup for an IP address.
bash
nslookup example.com
nslookup 93.184.216.34Output
Server: 192.168.1.1
Address: 192.168.1.1#53
Non-authoritative answer:
Name: example.com
Address: 93.184.216.34
Server: 192.168.1.1
Address: 192.168.1.1#53
34.216.184.93.in-addr.arpa name = example.com.
Common Pitfalls
Common mistakes when using nslookup include:
- Not specifying a domain or IP, which just opens interactive mode.
- Confusing forward lookup (domain to IP) with reverse lookup (IP to domain).
- Using outdated or unreachable DNS servers, causing no response.
Always check your DNS server settings if queries fail.
bash
nslookup # This opens interactive mode, not a direct query # Correct usage: nslookup example.com
Quick Reference
| Command | Description |
|---|---|
| nslookup example.com | Get IP address of example.com |
| nslookup 8.8.8.8 | Find domain name for IP 8.8.8.8 (reverse lookup) |
| nslookup example.com 8.8.8.8 | Query example.com using DNS server 8.8.8.8 |
| nslookup -type=MX example.com | Find mail servers for example.com |
| nslookup -debug example.com | Show detailed query info |
Key Takeaways
Use
nslookup [domain] to find the IP address of a domain.Use
nslookup [IP] for reverse DNS lookup to find the domain name.Specify a DNS server after the domain or IP to query a specific server.
Avoid running
nslookup without arguments unless you want interactive mode.Check your DNS server settings if queries do not return results.