Mastering UniFi DNS Resolver: A Complete Guide

The DNS resolver plays a critical role in managing network efficiency and security. This blog delves into the working of the DNS resolver UniFi. We'll touch upon its configuration, and best practices for optimizing your network.

Let's dive in!

Table of Contents

• What is a DNS Resolver?
• How Does a DNS Resolver Work?
• Configuring UniFi DNS Resolver
  • Access the UniFi Network Controller
  • Configure DNS Settings
  • Save and Apply
• Best Practices for DNS Resolver Configuration
• Troubleshooting Common DNS Issues
• Advanced DNS Configuration
  • Local DNS Resolver
  • DNS Forwarding
• Final Thoughts

What is a DNS Resolver?

A DNS (Domain Name System) resolver is an essential component that translates human-friendly domain names (like www.example.com) into IP addresses (like 192.0.2.1), which computers use to communicate with each other. In the context of UniFi, a DNS resolver ensures that devices within the network can efficiently locate and connect to external and internal resources.

How Does a DNS Resolver Work?

1. Query Initiation: When a user attempts to visit a website, their device sends a DNS query to the DNS resolver to find the corresponding IP address for the given domain name.

2. Recursive Query: The DNS resolver initiates a recursive query, meaning it will take responsibility for finding the final IP address, starting from the root DNS servers and working its way down.

3. Root Server Query: The resolver first contacts one of the root DNS servers, which respond with the details of the authoritative servers for the top-level domain (TLD) of the requested domain.

4. TLD Server Query: The resolver then queries the TLD server, which directs it to the authoritative DNS server for the specific domain.

5. Authoritative DNS Server Query: Finally, the resolver queries the authoritative DNS server, which provides the IP address for the requested domain.

6. Response to Client: The resolver returns the IP address to the user's device, enabling the browser to establish a connection with the target website.

Configuring UniFi DNS Resolver

Setting up the DNS resolver on UniFi devices involves configuring the DNS settings on the UniFi Controller. Here’s a step-by-step guide:

Access the UniFi Network Controller

1. Log into your UniFi Network Controller through your web browser.
2. Navigate to the main dashboard.

Configure DNS Settings

1. Navigate to Settings: Click on the 'Settings' icon in the left-hand menu.
2. Network Settings: Under the 'Networks' section, select the network you wish to configure.
3. Advanced Options: Scroll down to 'Advanced Options' and expand it.
4. DNS Server: Here, you can set the primary and secondary DNS servers for your network. You can use public DNS services like Google (8.8.8.8, 8.8.4.4) or Cloudflare (1.1.1.1, 1.0.0.1), or specify your own DNS server if you have one.

Save and Apply

1. Click 'Save' to apply the changes.
2. Your UniFi network will now use the specified DNS servers for resolving domain names.

Best Practices for DNS Resolver Configuration

1. Use Reliable DNS Servers: Choose DNS servers known for their reliability and speed, such as Google DNS, Cloudflare DNS, or OpenDNS.
2. Enable DNSSEC: DNS Security Extensions (DNSSEC) adds an extra layer of security by ensuring that the responses to DNS queries have not been tampered with.
3. Cache Optimization: Utilize caching to speed up DNS resolution times. Caching stores previously resolved domain names, reducing the need for repeated queries.
4. Monitor DNS Performance: Regularly monitor DNS query performance and troubleshoot any latency issues. Tools like nslookup or dig can help diagnose DNS problems.
5. Redundancy: Always configure a secondary DNS server to ensure continuous resolution in case the primary server fails.

Troubleshooting Common DNS Issues

• DNS Propagation Delays: Changes to DNS records can take time to propagate. Be patient and use tools like whatsmydns.net to check the status across various servers.
• DNS Spoofing: Protect against DNS spoofing by using DNSSEC and regularly updating your DNS resolver settings.
• Query Timeouts: Ensure your network is correctly configured and there are no connectivity issues with your DNS servers. Check for firewalls or security settings that might block DNS traffic.

Advanced DNS Configuration

For more advanced configurations, such as setting up a local DNS resolver or integrating with other network services, UniFi provides flexible options:

Local DNS Resolver

A local DNS resolver can improve network performance by reducing the need for external DNS queries. Here’s how to set it up:

1. Install a DNS Server: Install a DNS server software like BIND on a local machine or server.
2. Configure UniFi Devices: Point your UniFi devices to use this local DNS server by setting its IP address in the DNS settings.
3. Cache Management: Ensure your local DNS server is configured to cache responses effectively to speed up subsequent queries.

DNS Forwarding

DNS forwarding allows your local DNS resolver to forward queries it cannot resolve locally to an external DNS server. This setup combines the benefits of local DNS resolution with the reliability of public DNS services.

1. Configure Forwarders: In your local DNS server configuration, specify the external DNS servers to forward unresolved queries.
2. Update UniFi DNS Settings: Ensure your UniFi devices are configured to use your local DNS resolver as their primary DNS server.

Final Thoughts

The DNS resolver is an important omponent of any network for efficient and secure resolution of domain names to IP addresses. Proper configuration and management of the UniFi DNS resolver can enhance network performance and security. By following best practices and troubleshooting common issues, you can maintain a robust and reliable DNS infrastructure.

At UniHosted, we specialize in managing UniFi controllers in the cloud. We make sure robust DNS resolution is a part of our service. Whether you’re a small business or a large MSP, our solutions can help you maintain a reliable and efficient network. If you would like me to personally walk you through UniHosted, you can schedule a call with me here.