nslookup Cheatsheet
Quick reference for querying DNS records and checking name resolution with nslookup
The `nslookup` command queries DNS servers for domain and reverse lookup records. This cheatsheet covers quick host lookups, record type queries, reverse DNS, interactive mode, and a few practical troubleshooting checks.
Basic Syntax
Core nslookup command forms.
| Command | Description |
|---|---|
nslookup example.com | Look up a domain using the default resolver |
nslookup example.com 8.8.8.8 | Query a specific DNS server |
nslookup -type=mx example.com | Query a specific record type |
nslookup 192.0.2.1 | Run a reverse DNS lookup |
nslookup | Start interactive mode |
Common Lookups
Quick checks for hostnames and addresses.
| Command | Description |
|---|---|
nslookup example.com | Look up A and AAAA records using the default resolver |
nslookup www.example.com | Check a hostname or subdomain |
nslookup localhost | Verify local name resolution |
nslookup 127.0.0.1 | Reverse lookup for the local loopback address |
nslookup 192.0.2.1 | Reverse lookup for a public IP address |
Record Types
Use -type to query specific DNS records.
| Command | Description |
|---|---|
nslookup -type=a example.com | Query IPv4 address records |
nslookup -type=aaaa example.com | Query IPv6 address records |
nslookup -type=mx example.com | Query mail exchanger records |
nslookup -type=ns example.com | Query authoritative name servers |
nslookup -type=txt example.com | Query TXT records |
nslookup -type=soa example.com | Query the SOA record |
nslookup -type=cname www.example.com | Check whether a hostname is an alias |
nslookup -type=any example.com | Run an ANY query |
Specific DNS Servers
Compare answers from different resolvers.
| Command | Description |
|---|---|
nslookup example.com 8.8.8.8 | Query Google Public DNS |
nslookup example.com 1.1.1.1 | Query Cloudflare DNS |
nslookup example.com 9.9.9.9 | Query Quad9 |
nslookup -type=mx example.com 8.8.8.8 | Query MX records from a specific resolver |
nslookup -type=txt example.com 1.1.1.1 | Compare TXT answers between resolvers |
Interactive Mode
Run multiple queries in one session.
| Command | Description |
|---|---|
nslookup | Open interactive mode |
set type=mx | Switch the active query type to MX |
set type=txt | Switch the active query type to TXT |
server 8.8.8.8 | Change the active DNS server |
example.com | Query a domain after entering interactive mode |
exit | Leave the interactive session |
Troubleshooting
Quick checks for common nslookup errors.
| Issue | Check |
|---|---|
NXDOMAIN | Verify the domain name and make sure it exists |
SERVFAIL | Try another resolver such as 8.8.8.8 or 1.1.1.1 |
Connection timed out; no servers could be reached | Check network access and verify /etc/resolv.conf |
Non-authoritative answer | Normal cached response from a resolver |
No answer | The queried record type is not set for that name |
Related Guides
Use these guides for fuller DNS troubleshooting workflows.
| Guide | Description |
|---|---|
| nslookup Command in Linux | Full nslookup guide with practical examples |
| How to Use the dig Command to Query DNS in Linux | Detailed dig guide for deeper DNS debugging |
| ping Cheatsheet | Quick connectivity checks before DNS troubleshooting |
| IP command cheatsheet | Inspect interfaces, addresses, and routes |
| curl Cheatsheet | Test HTTP reachability after DNS resolution succeeds |