Azure多Web App虚拟网络接入及自定义DNS配置技术咨询
Hey there, let's break this down clearly for you:
Core Conclusion
You cannot use web-app-1 (already connected to your VNet) as a bridge to let web-app-2 and web-app-3 access the VNet or use its custom DNS servers. Each Azure Web App has its own isolated network stack—even if they're in the same App Service plan, the VNet integration settings of one app don't extend to others. There's no built-in mechanism for Web Apps to share network access or DNS configurations through a peer app.
Viable Solutions
You have two practical paths to achieve your goal:
1. Connect Each Web App Directly to the VNet
This is the simplest approach for your current setup:
- For web-app-2 and web-app-3, navigate to their individual Networking settings in the Azure Portal
- Go to VNet Integration and select your existing VNet (the one with custom DNS configured)
- Ensure the VNet's integration subnet meets Azure's requirements: it must be a dedicated subnet with no other resources, and have a minimum size of
/29(8 IP addresses) - Once connected, these Web Apps will automatically inherit the VNet's custom DNS server settings, just like web-app-1 does
2. Migrate to an App Service Environment (ASE)
If you expect to add more apps needing shared VNet access long-term, an ASE is a better scalable solution:
- An ASE is a fully isolated App Service deployment that lives entirely inside your VNet
- Every Web App deployed to the ASE automatically uses the VNet's DNS and network policies—no per-app VNet integration setup needed
- Note that ASEs carry higher costs and more management overhead, so this is ideal for scenarios with strict network isolation requirements
Quick DNS Note
Once a Web App is connected to your VNet, it will automatically use the custom DNS servers configured in the VNet's settings. You don't need to set DNS separately at the Web App level, unless you have edge cases like split DNS for specific domains.
内容的提问来源于stack exchange，提问作者Aravind Muraleedharan
