An Azure service that provides a platform-managed, scalable, and highly available application delivery controller as a service.
Hello @MohitNigam-9331 ,
You may refer to the below articles for more information on how to configure multi-tenant back ends such as App service with Application Gateway:
https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-web-app-overview
https://learn.microsoft.com/en-us/azure/application-gateway/configure-web-app-portal
In your scenario, you can make use of multi-site listeners and create 2 listeners with respective hostnames - custA.mydomain.com & custB.mydomain.com.
Add App service as backend pool.
Create HTTP settings for App service.
Make use of Override host header in the request in your HTTP settings.
Create Rule to tie the Listener, Backend Pool and HTTP Setting.
For information on Troubleshooting App Service issues in Application Gateway, please refer:
https://learn.microsoft.com/en-us/azure/application-gateway/troubleshoot-app-service-redirection-app-service-url
Kindly let us know if the above helps or you need further assistance on this issue.
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