How is the Gateway Url set in Azure APIM with multiple custom domains

Question

When the Azure API Management instance is configured with multiple custom domains, how is the default gateway url determined?

For eg: Below there are two custom domains configured. devpoc-api..com and dev-api..com

On APIM instance in the azure portal, the gateway URL shown is devpoc-api.*.com

Answer 1

@Nagashree Balasundaram Based on my understanding, you have configured multiple custom domains for Gateway but in the portal, Gateway URL was shown "devpoc-api.*.com" and would like to understand why.

By default, it points to https://<apim-name>.azure-api.net. After you set up custom domains, it will sort based on certificate, defaultSSLBinding in HostnameConfiguration if available for HostnameType DeveloperPortal, or default to first custom domain. This value cannot be changed and normally this will not affect any use scenario.

If you are concerned about default certificates issues for Gateway, check out How API Management proxy server responds with SSL certificates in the TLS handshake which describes more on that topic.

For any other questions, feel free to reach out. Would be happy to answer any.