[English] Debian Almquist Shell (dash) dig : Query DNS information

Overview

The dig command, short for Domain Information Groper, is a powerful tool used for querying DNS (Domain Name System) servers. It helps users retrieve information about domain names, such as IP addresses, mail servers, and other DNS records.

Usage

The basic syntax of the dig command is as follows:

dig [options] [arguments]

Common Options

@server: Specifies the DNS server to query.
-t type: Defines the type of DNS record to retrieve (e.g., A, MX, TXT).
+short: Provides a concise output, showing only the answer section.
-x address: Performs a reverse lookup, converting an IP address to a domain name.
+trace: Traces the delegation path from the root DNS servers to the authoritative server.

Common Examples

Here are some practical examples of using the dig command:

Querying an A record:
```
dig example.com
```
Querying a specific DNS record type (MX):
```
dig -t MX example.com
```
Using a specific DNS server:
```
dig @8.8.8.8 example.com
```
Performing a reverse DNS lookup:
```
dig -x 8.8.8.8
```
Getting a short answer:
```
dig +short example.com
```
Tracing the DNS resolution path:
```
dig +trace example.com
```

Tips

Use the +short option for quick lookups when you only need the answer.
When troubleshooting DNS issues, the +trace option can help you understand where the resolution process is failing.
Always specify a DNS server with the @server option if you want to test against a specific server, especially if you suspect local DNS caching issues.