How do I validate an Azure Host Name when the hostname record type is A

Question

I published my webforms site to Azure and now want to set up a subdomain to point to it.

In Azure, app service->Custom domains-> Custom Hostnames -> Add hostname

I selected A record for the Hostname record type.

However when I click Validate the Hostname record type reverts to CName How do I validate an A record ?

[Update] I see from this link that CName records are recommended.

Overwriting my choices when I click validate is a strange way of enforcing the recommendation though.

Answer 1

The system detects the record type automatically according to the hostname when you validate it. It's not recommended to choose the record type manually.

There are two steps to map a custom domain.

1. Create one record card in your DNS provider.
2. Add the hostname in Azure portal.

If you haven't created any record, what you have done is just to validate the availability of the hostname you input. Azure will remind you of the ownership as bellow.

If you have created an A record, and the record type reverted to CNAME after validation, which means you have specified a subdomain like www.contososo.com. The A record is only used to map root domain like contososo.com.

To map domain using A record, you need to create two records. Here's the example.

If you want to use CNAME or get more details, you can refer to the link you mentioned.