Troubleshooting DNS with dig and nslookup

When your domain is not resolving correctly, two of the most useful tools for diagnosing DNS issues are dig (on Linux/macOS) and nslookup (on Windows). These tools let you query DNS servers directly to see how your domain is configured.

Why Use These Tools?

• Verify if your domain points to the correct IP address.

• Check if DNS propagation is complete.

• Inspect specific DNS records (A, MX, CNAME, TXT, etc.).

• Identify misconfigurations between your registrar and hosting provider.

Using Web-Based DNS Tools

If you’re not comfortable with the command line, you can use free online tools:

• whatsmydns.net → Check global DNS propagation.

• digwebinterface.com → Run dig queries online.

Using nslookup on Windows

1. Open Command Prompt.

2. Run a basic query:

   Bash
   
   nslookup example.com
   

   → Shows the IP address (A record) for the domain.

3. Query a specific DNS server→

   Bash
   
   nslookup example.com 8.8.8.8
   

   
   Uses Google DNS (8.8.8.8) instead of your default resolver.

4. Look up MX (mail) records:

   Bash
   
   nslookup
   set type=MX
   example.com
   

Using dig on Linux/macOS

1. Open Terminal.

2. Run a basic query:

   Bash
   
   dig example.com
   

   → Displays the A record for the domain.

3. Query a specific DNS server:

   Bash
   
   dig @8.8.8.8 example.com
   

4. Look up MX records:

   Bash
   
   dig example.com MX
   

5. Look up TXT records (useful for SPF/DKIM):

   Bash
   
   dig example.com TXT
   

Interpreting Results

• ANSWER SECTION → Shows the record returned (e.g., IP address for A record).

• AUTHORITY SECTION → Shows which nameservers are authoritative for the domain.

• ADDITIONAL SECTION → May include related records (like IPs of nameservers).