Can we implement azure communication service with an existing email domain already registered in external DNS

Question

I have below questions related to Azure Communication services (ACS) SMTP Relay

1. Can we implement azure communication service SMTP Relay with an existing email domain (example domain name is swaplog.com) already registered in external DNS. This domain already has email address in it and users are using the domain to receive email. If yes, please let me know the steps as i don't want to create a new subdomain or azure subdomain and use the existing email domain for azure communication services
2. Is ACS SMTP Relay available for GCC High tenant
3. Is any cost involved for ACS SMTP Relay if you use new subdomain or azure subdomain or existing email domain (legacy smtp is free of charge thats why i have to know before moving to ACS)

Answer 1

Thanks for posting your question in the Microsoft Q&A forum.

1. Using Existing Email Domain with ACS SMTP Relay

You can use your existing domain without creating a new subdomain, Here are the steps:

• Add Custom Domain in Azure Portal
• Verify Domain Ownership
• Configure SPF and DKIM Authentication
• Attach Domain to ACS Resource

2. GCC High Tenant Availability

As of April 2025, ACS SMTP Relay is not available in GCC High tenants.

3. Cost Structure

ACS SMTP Relay pricing depends on:

• Emails sent
• Data transferred

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Answer 2

I already have my domain (example swaplog.com) registered in external DNS with DKIM and SPF authentication. Will it work ?