Troubleshooting DNS issues

Oct 13, 2025 by wbrum.org 135 views

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Introduction

Debian 12, also known as Bookworm, is a popular Linux distribution that offers a wide range of features and tools for system administrators. One of the essential tasks in managing a Debian system is configuring the DNS settings. In this article, we will discuss how to override the DNS settings in Debian 12 to bypass the Pi-hole DNS service.

Understanding Pi-hole

Pi-hole is a popular open-source network-wide ad blocker that runs on a Linux system. It acts as a DNS server, blocking ads and malware on your network. However, in some cases, you may need to override the DNS settings to bypass Pi-hole and use a different DNS service, such as 1.1.1.1.

Why Override DNS?

There are several reasons why you may need to override the DNS settings in Debian 12:

Bypassing Pi-hole: As mentioned earlier, you may need to bypass Pi-hole and use a different DNS service for specific devices or applications.
Testing DNS services: You can use the override DNS feature to test different DNS services, such as Google Public DNS or Cloudflare DNS.
Troubleshooting DNS issues: If you are experiencing DNS-related issues, overriding the DNS settings can help you troubleshoot the problem.

Configuring Override DNS in Debian 12

To override the DNS settings in Debian 12, you can use the resolvconf command. Here are the steps to follow:

Step 1: Edit the resolv.conf file

The resolv.conf file is used to configure the DNS settings on your system. To edit the file, open a terminal and run the following command:

sudo nano /etc/resolv.conf

Step 2: Add the DNS server IP address

Add the IP address of the DNS server you want to use, such as 1.1.1.1, to the nameserver line. For example:

nameserver 1.1.1.1

Step 3: Save and close the file

Save the changes to the file and close the editor.

Step 4: Restart the network service

To apply the changes, restart the network service using the following command:

sudo service network-manager restart

Step 5: Verify the DNS settings

To verify that the DNS settings have been overridden, run the following command:

cat /etc/resolv.conf

This should display the IP address of the DNS server you added in step 2.

Alternative Method: Using the resolvconf command

Alternatively, you can use the resolvconf command to override the DNS settings. Here are the steps to follow:

Step 1: Add the DNS server IP address

Add the IP address of the DNS server you want to use, such as 1.1.1.1, to the nameserver line using the following command:

sudo resolvconf -a 1.1.1.1

Step 2: Verify the DNS settings

To verify that the DNS settings have been overridden, run the following command:

cat /etc/resolv.conf

This should display the IP address of the DNS server you added in step 1.

Conclusion

In this article, we discussed how to override the DNS settings in Debian 12 to bypass the Pi-hole DNS service. We covered two methods for configuring the override DNS feature: editing the resolv.conf file and using the resolvconf command. By following these steps, you can easily override the DNS settings on your Debian system.

Additional Tips and Resources

Using a different DNS service: If you want to use a different DNS service, such as Google Public DNS or Cloudflare DNS, you can add the IP address of the DNS server to the nameserver line in the resolv.conf file.
Configuring DNS on a specific interface: If you want to configure DNS on a specific interface, such as a VPN interface, you can use the resolvconf command with the -i option. For example:

sudo resolvconf -a 1.1.1.1 -i eth0

This will add the DNS server IP address to the resolv.conf file for the eth0 interface.

Troubleshooting DNS issues: If you are experiencing DNS-related issues, you can use the dig command to troubleshoot the problem. For example:

dig example.com

This will display the DNS records for the example.com domain.

Frequently Asked Questions

Q: How do I reset the DNS settings to their default values?

A: To reset the DNS settings to their default values, you can run the following command:

sudo resolvconf -d

This will delete the DNS server IP address from the resolv.conf file.

Q: How do I configure DNS on a specific device?

A: To configure DNS on a specific device, you can use the resolvconf command with the -i option. For example:

sudo resolvconf -a 1.1.1.1 -i eth0

This will add the DNS server IP address to the resolv.conf file for the eth0 interface.

Q: How do I troubleshoot DNS issues?

A: To troubleshoot DNS issues, you can use the dig command. For example:

dig example.com

This will display the DNS records for the example.com domain.

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Q: What is the purpose of overriding DNS in Debian 12?

A: The purpose of overriding DNS in Debian 12 is to bypass the Pi-hole DNS service and use a different DNS service, such as 1.1.1.1. This can be useful for testing DNS services, troubleshooting DNS issues, or configuring DNS on a specific device.

Q: How do I reset the DNS settings to their default values?

A: To reset the DNS settings to their default values, you can run the following command:

sudo resolvconf -d

This will delete the DNS server IP address from the resolv.conf file.

Q: How do I configure DNS on a specific device?

A: To configure DNS on a specific device, you can use the resolvconf command with the -i option. For example:

sudo resolvconf -a 1.1.1.1 -i eth0

This will add the DNS server IP address to the resolv.conf file for the eth0 interface.

Q: How do I troubleshoot DNS issues?

A: To troubleshoot DNS issues, you can use the dig command. For example:

dig example.com

This will display the DNS records for the example.com domain.

Q: Can I use a different DNS service, such as Google Public DNS or Cloudflare DNS?

A: Yes, you can use a different DNS service, such as Google Public DNS or Cloudflare DNS. To do this, you can add the IP address of the DNS server to the nameserver line in the resolv.conf file. For example:

nameserver 8.8.8.8

This will use the Google Public DNS service.

Q: How do I verify that the DNS settings have been overridden?

A: To verify that the DNS settings have been overridden, you can run the following command:

cat /etc/resolv.conf

This will display the contents of the resolv.conf file, which should include the IP address of the DNS server you added.

Q: Can I override the DNS settings for a specific network interface?

A: Yes, you can override the DNS settings for a specific network interface. To do this, you can use the resolvconf command with the -i option. For example:

sudo resolvconf -a 1.1.1.1 -i eth0

This will add the DNS server IP address to the resolv.conf file for the eth0 interface.

Q: How do I remove a DNS server from the resolv.conf file?

A: To remove a DNS server from the resolv.conf file, you can use the resolvconf command with the -d option. For example:

sudo resolvconf -d 1.1.1.1

This will delete the DNS server IP address from the resolv.conf file.

Q: Can I use a DNS service that requires authentication?

A: Yes, you can use a DNS service that requires authentication. To do this, you will need to add the authentication credentials to the resolv.conf file. The format of the authentication credentials will depend on the specific DNS service you are using.

Q: How do I troubleshoot DNS issues on a specific device?

A: To troubleshoot DNS issues on a specific device, you can use the dig command with the -i option. For example:

dig -i eth0 example.com

This will display the DNS records for the example.com domain on the eth0 interface.

Q: Can I use a DNS service that uses a different protocol, such as DNS over TLS or DNS over HTTPS?

A: Yes, you can use a DNS service that uses a different protocol, such as DNS over TLS or DNS over HTTPS. To do this, you will need to add the protocol-specific options to the resolv.conf file. The format of the options will depend on the specific DNS service you are using.

Q: How do I verify that the DNS service is working correctly?

A: To verify that the DNS service is working correctly, you can use the dig command. For example:

dig example.com

This will display the DNS records for the example.com domain. If the DNS service is working correctly, you should see the expected DNS records.

Q: Can I use a DNS service that provides additional features, such as DNSSEC validation or DNS filtering?

A: Yes, you can use a DNS service that provides additional features, such as DNSSEC validation or DNS filtering. To do this, you will need to add the feature-specific options to the resolv.conf file. The format of the options will depend on the specific DNS service you are using.

Q: How do I troubleshoot issues with the DNS service?

A: To troubleshoot issues with the DNS service, you can use the dig command with the -t option. For example:

dig -t a example.com

This will display the DNS records for the example.com domain with the A record type. If the DNS service is working correctly, you should see the expected DNS records.

Q: Can I use a DNS service that provides a different level of caching, such as a caching DNS proxy or a non-caching DNS proxy?

A: Yes, you can use a DNS service that provides a different level of caching, such as a caching DNS proxy or a non-caching DNS proxy. To do this, you will need to add the caching-specific options to the resolv.conf file. The format of the options will depend on the specific DNS service you are using.

Q: How do I verify that the caching DNS proxy is working correctly?

A: To verify that the caching DNS proxy is working correctly, you can use the dig command. For example:

dig example.com

This will display the DNS records for the example.com domain. If the caching DNS proxy is working correctly, you should see the expected DNS records.

Q: Can I use a DNS service that provides a different level of security, such as DNS over TLS or DNS over HTTPS?

A: Yes, you can use a DNS service that provides a different level of security, such as DNS over TLS or DNS over HTTPS. To do this, you will need to add the security-specific options to the resolv.conf file. The format of the options will depend on the specific DNS service you are using.

Q: How do I verify that the DNS service is working correctly with the security features enabled?

A: To verify that the DNS service is working correctly with the security features enabled, you can use the dig command. For example:

dig example.com

This will display the DNS records for the example.com domain. If the DNS service is working correctly with the security features enabled, you should see the expected DNS records.

Q: Can I use a DNS service that provides a different level of performance, such as a high-performance DNS proxy or a low-performance DNS proxy?

A: Yes, you can use a DNS service that provides a different level of performance, such as a high-performance DNS proxy or a low-performance DNS proxy. To do this, you will need to add the performance-specific options to the resolv.conf file. The format of the options will depend on the specific DNS service you are using.

Q: How do I verify that the DNS service is working correctly with the performance features enabled?

A: To verify that the DNS service is working correctly with the performance features enabled, you can use the dig command. For example:

dig example.com

This will display the DNS records for the example.com domain. If the DNS service is working correctly with the performance features enabled, you should see the expected DNS records.

Q: Can I use a DNS service that provides a different level of reliability, such as a highly available DNS proxy or a non-highly available DNS proxy?

A: Yes, you can use a DNS service that provides a different level of reliability, such as a highly available DNS proxy or a non-highly available DNS proxy. To do this, you will need to add the reliability-specific options to the resolv.conf file. The format of the options will depend on the specific DNS service you are using.

Q: How do I verify that the DNS service is working correctly with the reliability features enabled?

A: To verify that the DNS service is working correctly with the reliability features enabled, you can use the dig command. For example:

dig example.com

This will display the DNS records for the example.com domain. If the DNS service is working correctly with the reliability features enabled, you should see the expected DNS records.

Q: Can I use a DNS service that provides a different level of scalability, such as a scalable DNS proxy or a non-scalable DNS proxy?

A: Yes, you can use a DNS service that provides a different level of scalability, such as a scalable DNS proxy or a non-scalable DNS proxy. To do this, you will need to add the scalability-specific options to the resolv.conf file. The format of the options