TLS/SSL Settings for Azure App Service
Securing your web applications is crucial. Azure App Service provides robust features to manage Transport Layer Security (TLS) and Secure Sockets Layer (SSL) certificates for your custom domains.
Understanding TLS/SSL in App Service
TLS/SSL is used to encrypt the HTTP traffic between your clients and your App Service application, ensuring data privacy and integrity. This is essential for sensitive information and for building user trust.
Configuring TLS/SSL Settings
You can configure TLS/SSL settings through the Azure portal, Azure CLI, or Azure PowerShell.
Binding Certificates
To enable HTTPS for your custom domain, you need to bind an SSL certificate to it. You have several options:
- App Service Managed Certificates: Free, auto-renewing certificates provided by Azure. Ideal for many scenarios.
- Import App Service Certificate: Purchase an App Service Certificate directly from Azure.
- Import/Upload a Certificate: Upload your own certificate purchased from a third-party Certificate Authority (CA).
Steps to Configure TLS/SSL
Using the Azure Portal
- Navigate to your App Service in the Azure portal.
- In the left-hand menu, under "Settings," select "TLS/SSL settings."
- Under the "Custom domains" tab, select your custom domain.
- Click "Add binding."
- Choose your certificate source (Managed, App Service Certificate, or Import/Upload).
- Select the certificate you want to use.
- Choose the TLS/SSL Type:
- SNI SSL: Server Name Indication allows multiple SSL certificates to be hosted on a single IP address. This is the most common and recommended option.
- IP SSL: Assigns a dedicated IP address to your App Service for SSL. This is less common and incurs additional costs.
- Click "Add binding" to complete the process.
Important: Ensure your custom domain is already mapped to your App Service before proceeding with certificate binding.
Managing Certificates
Within the "TLS/SSL settings" blade, you can also:
- View all uploaded and managed certificates.
- Renew or re-import certificates.
- Delete certificates that are no longer needed.
Enforcing HTTPS
To ensure all traffic to your App Service uses HTTPS, you should enforce it:
- In the "TLS/SSL settings" blade, under "App Service settings," find the "HTTPS Only" option.
- Set it to "On."
Certificate Stores
Certificates can be stored in the App Service's certificate store or Key Vault for enhanced security and management.
Troubleshooting Common Issues
- Certificate Expiration: Regularly monitor certificate expiration dates, especially for manually uploaded certificates.
- Incorrect Binding: Ensure the correct certificate is bound to the correct custom domain.
- SNI vs. IP SSL: Understand the implications of SNI and IP SSL for your application's needs and cost.
For detailed command-line examples, refer to the Azure CLI and Azure PowerShell documentation.