Domain Limits

Question

I have 2 IIS servers on Azure that present content based on the domain name. 280 domains are pointed to it at the moment on our current WAF solution.
Looking at the App Gateway WAF v2 but I'm not sure if it can support all the domain names. For SSL I use a single certificate with many SAN on it.

Will I be able to use the App Gateway WAF v2? If not, is there an alternative?

Answer 1

@Danny Chrismas , As of now APGW listener limit is set to 100 per GW. Here is a feature request on similar ask requesting to allow multiple hostnames in the same listener. I would recommend you to upvote the same and provide your feedback for its future availability.

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Answer 2

@Danny Chrismas - How about the below solution ?

1. A backend pool with both the IIS servers
2. One basic type HTTPS listener to serve all the 280 domains
3. One HTTP Settings, you may choose to offload the SSL here
4. A request routing rule
5. Custom probe may require if your backends doesn't respond to the default health probe on http://127.0.0.1/

With the above configuration in place, a basic HTTPS listener would accept traffic from multiple hostnames and proxy those requests to the same backend server. Let the backend respond to the domain names it has.

More about basic type listener: https://learn.microsoft.com/en-us/azure/application-gateway/configuration-listeners#listener-type

Also App Gateway does support SAN certificates: https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-faq#what-certificates-does-application-gateway-support

If you would like to proceed with the Multi-Site listener then you would encounter the limit - https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/azure-subscription-service-limits#application-gateway-limits

If you are planning to enable WAF then the recommended limit is the 40 listeners.
Hope this helps !