dig and nslookup are common command-line tools for querying DNS records, suitable for network troubleshooting and domain name resolution verification. 1. The usage of dig includes: directly enter dig example.com to query A record, use dig example.com MX to view MX records, dig short displays concise results, dig @8.8.8.8 example.com to specify the DNS server; 2. The basic usage of nslookup is nslookup example.com, and A record is displayed by default. Switch query types by set type=MX, nslookup example.com 8.8.8.8 to specify the DNS server. Both have their own characteristics. The dig output is clear and suitable for fast queries, and nslookup supports interactive multiple queries. Pay attention to permissions, platform differences, cache impact and firewall restrictions when using it.

Querying DNS records is a very common operation in network troubleshooting, domain name resolution verification, and server configuration. dig and nslookup are two commonly used command line tools that can be used to view domain name A records, CNAME, MX, TXT and other information. Although they are similar in function, they are used slightly differently.

Query DNS records using dig

dig (Domain Information Groper) is a powerful and clear DNS query tool that is widely used in Linux and macOS systems.

Basic usage:

 dig example.com

This command returns the A record of example.com , and will also display some additional information by default, such as authoritative DNS servers and additional records.

Common options:

• View specific types of records:

   dig example.com MX

  This allows you to check only the MX records of the mail server.

• Show only the answer part (concise output):

   dig short example.com A

• Specify DNS server query:

   dig @8.8.8.8 example.com

  This method is often used to test whether a particular DNS returns the correct resolution.

Use nslookup to query DNS records

nslookup is another classic DNS query tool that supports both Windows and Unix systems. Compared to dig , its interactive style is a little stronger, but the output format is a bit old.

Basic usage:

 nslookup example.com

By default, the A record and the corresponding DNS server will be displayed.

Switch query type: Enter the following content on the command line to switch query type:

 nslookup
> set type=MX
> example.com

This way you can find the MX record of example.com .

Specify the DNS server:

 nslookup example.com 8.8.8.8

This means using Google's public DNS to resolve example.com .

Frequently Asked Questions and Precautions

1. Permissions Issue: Administrator permissions may be required on some systems to run these commands.
2. Cross-platform difference: The nslookup output format on Windows is different from Linux, and some parameters are not supported.
3. Cache Impact: If the local or DNS server has cache, you may see old resolution results.
4. Firewall Restrictions: Some network environments may block access to non-default DNS ports.

If you just want to quickly confirm whether a domain name is parsing normally, it is more convenient to use dig ; and if you need to query different types interactively multiple times, nslookup is also very useful.

Basically that's it. If you master the basic usage of these two tools, you will have no major problems in daily troubleshooting DNS-related issues.

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