# nslookup Command Reference
## What it does
Queries DNS servers to lookup domain names, IP addresses, and various DNS record types for troubleshooting.
## Basic Usage
```bash
nslookup google.com # Basic domain lookup
nslookup 8.8.8.8 # Reverse DNS lookup
nslookup google.com 1.1.1.1 # Use specific DNS server
```
## Record Type Queries
| Record Type | Command | Description |
|-------------|---------|-------------|
| `A` | `nslookup -type=A domain.com` | IPv4 address |
| `AAAA` | `nslookup -type=AAAA domain.com` | IPv6 address |
| `MX` | `nslookup -type=MX domain.com` | Mail exchange |
| `NS` | `nslookup -type=NS domain.com` | Name servers |
| `TXT` | `nslookup -type=TXT domain.com` | Text records |
| `CNAME` | `nslookup -type=CNAME domain.com` | Canonical name |
## Interactive Mode
```bash
# Start interactive session
nslookup
> google.com
> set type=MX
> github.com
> exit
```
## Advanced Options
```bash
# Query specific DNS server
nslookup google.com 8.8.8.8
# Set query timeout
nslookup -timeout=5 google.com
# Debug mode (verbose output)
nslookup -debug google.com
# Query class (usually IN for Internet)
nslookup -class=IN google.com
```
## Common Arguments
| Argument | Description |
|----------|-------------|
| `-type=TYPE` | Specify record type to query |
| `-timeout=N` | Set query timeout in seconds |
| `-debug` | Enable debug output |
| `-port=N` | Use specific port (default 53) |
## Quick Commands
```bash
# Basic domain info
nslookup google.com
# Mail servers for domain
nslookup -type=MX gmail.com
# Name servers for domain
nslookup -type=NS apple.com
# Reverse IP lookup
nslookup 142.250.191.46
# Use Cloudflare DNS
nslookup github.com 1.1.1.1
```
## Reading Results
```bash
Server: 192.168.1.1
Address: 192.168.1.1#53
Non-authoritative answer:
Name: google.com
Address: 142.250.191.46
```
- `Server` → DNS server used for query
- `Non-authoritative` → Answer from cache, not original source
- `Address` → IP address result
## Pro Tips
> - Use specific DNS servers to test different resolvers
> - Interactive mode useful for multiple queries
> - Compare results from different DNS servers to troubleshoot