Update .NET Domains by January 7, 2025 | Critical Developer Advisory

Critical Deadline: Update .NET Domains Before January 7, 2025, to Avoid Service Disruption

The clock is ticking for developers and organizations using Microsoft’s .NET infrastructure. A critical directive from Microsoft requires users to update .NET domains by January 7, 2025, as the company transitions from Edgio-hosted Azure Content Delivery Networks (CDNs) to Azure Front Door. This shift, prompted by Edgio’s imminent shutdown, has significant implications for service availability, security, and operational continuity.

Acting promptly to update .NET domains is crucial to avoid downtime and mitigate security risks. This guide provides a comprehensive overview of the changes, their implications, and actionable steps to ensure a seamless migration.

What’s Changing and Why?

For years, Microsoft has used domains like dotnetcli.azureedge.net and dotnetbuilds.azureedge.net to distribute .NET binaries and installers. These domains are hosted on Edgio, a CDN provider that recently faced financial challenges, leading to its acquisition by Akamai. As part of the transition, Edgio’s platform is scheduled to shut down on January 15, 2025, prompting Microsoft to migrate its infrastructure to Azure Front Door, a more reliable and scalable CDN solution.

Key Changes to Note:

1. Domain Migration:
   • Microsoft will automatically migrate workloads using Edgio domains to Azure Front Door by January 7, 2025.
   • However, endpoints using *.vo.msecnd.net cannot be automatically migrated.
2. Configuration Freeze:
   • Starting January 3, 2025, users cannot update configurations for Azure CDN by Edgio profiles. Services will remain operational until either migration occurs or the platform shuts down.
3. Custom Domains Recommended:
   • Microsoft advises users to transition to custom domains for greater flexibility and resilience against future disruptions.
4. Security Precautions:
   • To prevent malicious actors from exploiting legacy domains, Microsoft has taken control of azureedge.net but still recommends users update references proactively.

Why Do You Need to Update .NET Domains?

Microsoft’s decision to migrate its CDN infrastructure stems from the impending shutdown of Edgio, the platform hosting dotnetcli.azureedge.net and dotnetbuilds.azureedge.net. Edgio’s financial troubles and subsequent acquisition by Akamai have necessitated this shift to Azure Front Door, a more reliable and scalable solution.

Key Reasons to Update .NET Domains:

1. Service Continuity: Failure to update .NET domains may lead to service disruptions after January 15, 2025, when the Edgio platform ceases operations.
2. Enhanced Security: Legacy domains could become vulnerable to cyberattacks, such as malware distribution or software supply chain poisoning.
3. Future Flexibility: Transitioning to custom domains reduces dependency on third-party platforms, ensuring greater control and reliability.

Steps to Update .NET Domains and Avoid Downtime

Step 1: Audit and Update Domain References

Conduct a comprehensive scan of your infrastructure, including codebases, CI/CD pipelines, and deployment configurations. Identify references to the following outdated domains:

• dotnetcli.azureedge.net
• dotnetcli.blob.core.windows.net

Update them to the new Microsoft-hosted domain:

• Replace with builds.dotnet.microsoft.com.

Use automated tools like grep (for Linux systems) or specialized code scanning tools to streamline this process. Be sure to document all updates for future audits.

Step 2: Prepare for Automatic Migration

For most users, workloads using Edgio-hosted domains will be automatically migrated to Azure Front Door by January 7, 2025. However, to customize your migration path:

1. Set the DoNotForceMigrateEdgioCDNProfiles feature flag before the January 7 deadline if you intend to use an alternative CDN provider.
2. Plan a manual migration to your preferred CDN, ensuring compliance with Microsoft’s guidelines.

Step 3: Adopt Custom Domains

Microsoft emphasizes the importance of transitioning to custom domains to reduce reliance on third-party CDNs. Benefits of custom domains include:

• Greater Flexibility: Control over DNS configurations allows easier transitions in the future.
• Reduced Risk: Eliminates dependency on specific platforms that may become obsolete.

For example:

• Instead of relying on azureedge.net, configure mycompany-cdn.com to point to your Azure Front Door resources.

Step 4: Test and Validate

After updating domain references and completing migration, thoroughly test your applications. Focus on:

• Build Pipelines: Ensure CI/CD workflows function as expected.
• Dependencies: Verify that all .NET binaries and installers are accessible.
• Performance: Monitor latency and throughput to identify potential bottlenecks.

Step 5: Monitor Key Dates

Set calendar reminders and allocate resources to ensure compliance with these deadlines.

Impact on DevOps and Operations

For Developers:

• Codebase Updates: Developers must update .NET domains in all projects and CI/CD pipelines.
• Pipeline Integrity: Testing pipelines is essential to prevent build or deployment failures after migration.

For IT Administrators:

• Custom CDN Configurations: Configure and validate custom domains for enhanced control.
• Performance Monitoring: After updating .NET domains, monitor system performance to identify potential bottlenecks.

Security Implications and Best Practices

With Edgio’s exit and potential vulnerabilities tied to legacy domains, the security landscape demands vigilance. Follow these best practices:

1. Monitor Network Traffic: Look for unusual activity tied to outdated domains.
2. Apply Patching Policies: Regularly update libraries and dependencies.
3. Adopt Zero-Trust Security Models: Limit access to critical resources based on least privilege principles.

By staying proactive, organizations can protect against supply chain attacks and ensure robust application security.

How to Ensure a Smooth Transition

1. Communicate Internally: Inform all relevant teams about the need to update .NET domains and ensure everyone is aligned on deadlines.
2. Test Thoroughly: Validate all changes in a staging environment before applying them in production.
3. Monitor Traffic: After migration, keep a close eye on network traffic to detect anomalies or errors tied to the changes.

Conclusion: Don’t Delay—Update .NET Domains Now

The directive to update .NET domains is not just another routine task—it’s a critical measure to maintain service reliability and security. With the January 7, 2025, deadline fast approaching, organizations must act swiftly to ensure a smooth transition. Whether you migrate to Azure Front Door or an alternative CDN, taking proactive steps now will safeguard your operations against future disruptions.

Key Takeaways:

• Audit and update domain references in your codebase and pipelines.
• Adopt custom domains for greater control and flexibility.
• Set necessary feature flags if you prefer a manual migration path.
• Monitor all changes closely to ensure uninterrupted service.

The time to act is now. Update your .NET domains today to avoid disruptions and protect your applications. Share this guide with your team and ensure everyone is prepared.