Configuring a custom domain name for an Azure cloud service (classic)

When you create a Cloud Service, Azure assigns it to a subdomain of cloudapp.net. For example, if your Cloud Service is named "contoso", your users will be able to access your application on a URL like http://contoso.cloudapp.net. Azure also assigns a virtual IP address.

However, you can also expose your application on your own domain name, such as contoso.com. This article explains how to reserve or configure a custom domain name for Cloud Service web roles.

Do you already understand what CNAME and A records are? Jump past the explanation.

Understand CNAME and A records

CNAME (or alias records) and A records both allow you to associate a domain name with a specific server (or service in this case,) however they work differently. There are also some specific considerations when using A records with Azure Cloud services that you should consider before deciding which to use.

CNAME or Alias record

A CNAME record maps a specific domain, such as contoso.com or www.contoso.com, to a canonical domain name. In this case, the canonical domain name is the [myapp].cloudapp.net domain name of your Azure hosted application. Once created, the CNAME creates an alias for the [myapp].cloudapp.net. The CNAME entry will resolve to the IP address of your [myapp].cloudapp.net service automatically, so if the IP address of the cloud service changes, you do not have to take any action.

A record

An A record maps a domain, such as contoso.com or www.contoso.com, or a wildcard domain such as *.contoso.com, to an IP address. In the case of an Azure Cloud Service, the virtual IP of the service. So the main benefit of an A record over a CNAME record is that you can have one entry that uses a wildcard, such as *.contoso.com, which would handle requests for multiple sub-domains such as mail.contoso.com, login.contoso.com, or www.contso.com.

Add a CNAME record for your custom domain

To create a CNAME record, you must add a new entry in the DNS table for your custom domain by using the tools provided by your registrar. Each registrar has a similar but slightly different method of specifying a CNAME record, but the concepts are the same.

1. Use one of these methods to find the .cloudapp.net domain name assigned to your cloud service.

   • Login to the Azure portal, select your cloud service, look at the Overview section and then find the Site URL entry.

     

     OR

   • Install and configure Azure PowerShell, and then use the following command:

     Get-AzureDeployment -ServiceName yourservicename | Select Url
     

     Save the domain name used in the URL returned by either method, as you will need it when creating a CNAME record.

2. Log on to your DNS registrar's website and go to the page for managing DNS. Look for links or areas of the site labeled as Domain Name, DNS, or Name Server Management.

3. Now find where you can select or enter CNAME's. You may have to select the record type from a drop down, or go to an advanced settings page. You should look for the words CNAME, Alias, or Subdomains.

4. You must also provide the domain or subdomain alias for the CNAME, such as www if you want to create an alias for www.customdomain.com. If you want to create an alias for the root domain, it may be listed as the '@' symbol in your registrar's DNS tools.

5. Then, you must provide a canonical host name, which is your application's cloudapp.net domain in this case.

For example, the following CNAME record forwards all traffic from www.contoso.com to contoso.cloudapp.net, the custom domain name of your deployed application:

Add an A record for your custom domain

To create an A record, you must first find the virtual IP address of your cloud service. Then add a new entry in the DNS table for your custom domain by using the tools provided by your registrar. Each registrar has a similar but slightly different method of specifying an A record, but the concepts are the same.

1. Use one of the following methods to get the IP address of your cloud service.

   • Login to the Azure portal, select your cloud service, look at the Overview section and then find the Public IP addresses entry.

     

     OR

   • Install and configure Azure PowerShell, and then use the following command:

     get-azurevm -servicename yourservicename | get-azureendpoint -VM {$_.VM} | select Vip
     

     Save the IP address, as you will need it when creating an A record.

2. Log on to your DNS registrar's website and go to the page for managing DNS. Look for links or areas of the site labeled as Domain Name, DNS, or Name Server Management.

3. Now find where you can select or enter A record's. You may have to select the record type from a drop down, or go to an advanced settings page.

4. Select or enter the domain or subdomain that will use this A record. For example, select www if you want to create an alias for www.customdomain.com. If you want to create a wildcard entry for all subdomains, enter '*****'. This will cover all sub-domains such as mail.customdomain.com, login.customdomain.com, and www.customdomain.com.

   If you want to create an A record for the root domain, it may be listed as the '@' symbol in your registrar's DNS tools.

5. Enter the IP address of your cloud service in the provided field. This associates the domain entry used in the A record with the IP address of your cloud service deployment.

For example, the following A record forwards all traffic from contoso.com to 137.135.70.239, the IP address of your deployed application:

This example demonstrates creating an A record for the root domain. If you wish to create a wildcard entry to cover all subdomains, you would enter '*****' as the subdomain.

Next steps

• How to Manage Cloud Services
• How to Map CDN Content to a Custom Domain
• General configuration of your cloud service.
• Learn how to deploy a cloud service.
• Configure TLS/SSL certificates.