How to configure Azure DNS for Custom Domain Names

In the dynamic realm of cloud computing and modern enterprise operations, Azure Active Directory (Azure AD) stands as a linchpin for secure identity management and access control. As organizations increasingly migrate their workflows to the cloud, the significance of a robust and adaptable identity management solution cannot be overstated. Managing Azure AD, customizing the Domain Name System (DNS) settings allows for enhanced control, security, and optimization of network resources. This article provides a comprehensive guide to configuring Azure AD DNS for custom domain names and delving deep into advanced settings.

Prerequisites

• Admin rights to Azure AD and the DNS hosting provider.
• A custom domain name registered through a domain registrar.

Configuring Azure AD Domain Name System for Custom Domain Names 

1. Add Custom Domain to Azure AD   

1. Navigate to Azure Portal and log in with your administrator credentials.
2. Click on “Azure Active Directory” > “Custom domain names”.
3. Click on “+ Add” and enter the custom domain name. Click on “Add Domain” to proceed.

2. Verify the Custom Domain   

1. Azure provides a verification ID to confirm ownership of the domain. Copy this ID.
2. Log in to DNS Hosting Provider  
3. Access the DNS management console of the domain registrar where the custom domain is registered.
4. Create a new TXT record, paste the Azure verification ID as the value, and save the changes.
5. Return to Azure AD and click on “Verify” to confirm domain ownership.

3. Configure Advanced DNS Settings

1. Navigate to “DNS zones” in Azure Portal. Click on the custom domain name.
2. Add DNS Records   by clicking the “+ Record set”.
3. Choose the type of DNS record (A, CNAME, MX, etc.) and enter the necessary information.

Testing the DNS Configuration in Azure

After configuring Azure AD DNS, testing the setup is a pivotal step to ensure that the configurations are successful and the DNS is resolving names accurately. A systematic approach in testing can ensure that all the configurations and settings align with the expected outcomes, ensuring seamless communication within your custom domain.

1. Verify the Success of Your DNS Configuration in Azure

To affirm the success of the DNS configuration, several methods can be employed. One effective way is to utilize built-in tools and utilities that are designed to query the Domain Name System and return useful information.

1. Use command-line tools like nslookup or dig to query your domain.

nslookup yourdomain.com

2. Analyze the output to ensure that it is pointing to the correct IP address and other associated records.
3. Confirm that all DNS records are propagating as expected globally.

2. Testing the DNS Configuration in Azure   

Testing your DNS involves several steps to ensure that every aspect of your configuration is functioning as intended.

1. Check DNS Records: Verify that all DNS records are correctly entered and propagating.
2. Test Name Resolution: Use various tools and methods to ensure names are resolving to the correct addresses.
3. Check Propagation: Ensure that DNS changes have propagated throughout all DNS servers globally.

3. Ensure Proper Name Resolution by Conducting Thorough DNS Tests   

Name resolution tests ensure that your domain and subdomains are resolving to the correct IP addresses, confirming that users are directed to the intended destinations.

1. Utilize online tools to check DNS propagation globally.
2. Conduct internal tests within your network to verify that internal name resolutions are accurate.
3. Test on different devices and networks to ensure consistency.

4. Validate the Accuracy of Your DNS Setup in Azure   

Validation of the DNS setup involves checking that all configurations, including advanced settings, are optimized for performance and security.

1. Review DNS records and settings in the Azure portal to ensure they match the intended configuration.
2. Test security settings like DNSSEC to confirm they are operational.
3. Utilize Azure’s monitoring and analytics tools to review performance metrics and anomalies.

5. Confirm Smooth Communication Within Your Custom Domain Using DNS Testing   

Ensuring that the internal and external communications are functioning smoothly is crucial. It validates that applications and services dependent on the DNS are accessible and operational.

1. Access applications and services within your custom domain to confirm they are reachable and functional.
2. Monitor network traffic to identify any anomalies or issues related to DNS resolution.
3. Use monitoring tools to set up alerts for any unexpected behaviours or outages.

Tools and Resources for Testing   

Various tools, both built-in within Azure and third-party, can be employed to facilitate comprehensive testing. These tools offer detailed insights into DNS performance, security, and integrity. Analyzing the reports and feedback from these tools aids in validating and, if necessary, refining the DNS configurations to ensure optimal performance.

Advanced Configuration   

If you are an experienced administrator looking to fine-tune your DNS settings for optimal performance, follow these technical steps:

i. TTL Setting Customization: 

Time To Live (TTL) settings dictate how long DNS records are cached by DNS resolvers and clients. Adjusting these settings can help control caching duration and improve DNS responsiveness.

1. Access your DNS management console or interface.
2. Locate the TTL settings for your DNS records. This is typically found in the DNS record creation or editing section.
3. Modify the TTL values for specific DNS records as needed. Lower values, such as 300 seconds (5 minutes), can reduce caching duration and facilitate quicker updates.
4. Save your changes and monitor the impact on DNS resolution performance.

ii. DNSSEC Implementation: 

DNS Security Extensions (DNSSEC) is a crucial security feature that safeguards against DNS spoofing and cache poisoning attacks. Enabling DNSSEC involves several technical steps:

1. Access your DNS management console or interface.
2. Generate cryptographic key pairs, including a Key Signing Key (KSK) and Zone Signing Key (ZSK). Tools like dnssec-keygen can help with this process.
3. Sign your DNS zone with these keys using a DNSSEC signing tool like dnssec-signzone.
4. Update your DNS registrar with the generated DS (Delegation Signer) records. This establishes the chain of trust.
5. Verify that DNSSEC is correctly configured using DNSSEC validation tools such as dnssec-verify.
6. Monitor DNSSEC status and renew keys periodically.

 iii. Traffic Manager Deployment: 

Azure Traffic Manager is a powerful tool for load balancing and traffic distribution across global endpoints. Here’s how to implement it:

1. Access your Azure portal and navigate to the Traffic Manager service.
2. Create a new Traffic Manager profile.
3. Configure the routing method (e.g., priority, weighted, performance) based on your requirements.
4. Add endpoints to the Traffic Manager profile. These endpoints can be Azure resources, external URLs, or on-premises resources.
5. Define monitoring settings to check the health of your endpoints. You can specify the protocol and port to monitor.
6. Set up DNS records for your application or service to point to the Traffic Manager’s DNS name, typically in the format of yourapp.trafficmanager.net.
7. Save your configuration and monitor traffic distribution and endpoint health through the Azure portal.

Next Steps After Configuring Azure AD DNS?   

With Azure AD DNS successfully configured, it’s vital to consider the subsequent steps to maximize the utility and efficiency of your DNS configuration. The following outlines a step-by-step guide to actions that administrators should contemplate to further optimize and secure their Azure AD DNS.

	Action	Benefit
Monitoring and Analytics	Activate monitoring and analytics tools within Azure to keep track of DNS health, traffic, and potential security threats.	Enhanced visibility and insights for proactive management and issue resolution.
Integration with Azure Services	Explore integration possibilities with other Azure services such as Azure Traffic Manager and Azure Security Center.	Enhanced DNS performance, security, and global reach.
Optimizing Security Protocols	Assess and enhance security protocols, including implementing DNS Security Extensions (DNSSEC) to secure DNS queries.	Protection against DNS spoofing and enhanced data integrity.
Performance Optimization	Regularly review and optimize the DNS performance metrics, and make necessary adjustments to ensure efficiency and speed.	Improved website and application load times and user experience.
Documentation and Compliance	Ensure that all configurations and changes are documented. Check compliance with organizational and regulatory standards.	Ease in audits and ensuring configurations adhere to required standards.
Training and Development	Train the team on the new features and functionalities unlocked with the Azure AD DNS to ensure effective utilization.	Enhanced team capability to manage and troubleshoot Azure AD DNS.
Disaster Recovery Planning	Develop and test a disaster recovery plan to ensure business continuity in case of any failures or cyber-attacks.	Minimized downtime and business impact during unforeseen events.
Feedback and Improvement	Gather feedback on the DNS performance and make continuous improvements to meet the dynamic organizational needs.	A more responsive and efficient DNS that aligns with organizational objectives.

Navigating Azure AD DNS Enhancements   

Azure AD DNS is not just about domain name resolution; it’s a gateway to enhanced security, performance, and integration with a myriad of Azure services. Each step post-configuration is geared towards elevating the operational efficiency, security posture, and the overall performance of applications and services reliant on the DNS.

Integration with Azure Ecosystem   

A noteworthy avenue to explore is the seamless integration of Azure AD DNS with the broader Azure ecosystem. This integration not only amplifies the performance but also introduces an array of features that can be customized to fit unique organizational needs.

Conclusion   

Configuring Azure AD DNS for custom domains requires a systematic approach involving the addition and verification of the custom domain, followed by advanced DNS settings configuration. By optimizing DNS settings, administrators can enhance network performance, reliability, and security. Always ensure to test the configurations to verify their impact on the network and application accessibility.