Check DNS Prefix Availability


Updated: July 10, 2015

The Check DNS Prefix Availability operation checks whether the specified DNS prefix is available for creating a profile.

The Check DNS Prefix Availability request is specified as follows. Replace <subscription-id> with the subscription ID. Replace <dns-name> with the DNS name that you want to use. You must include in the name.


Request URI


You must make sure that the request that is made to the management service is secure. For additional details, see Authenticating Service Management Requests.

The following table describes the request headers.

Request Header



Required. Specifies the version of the operation to use for this request. This header should be set to 2011-10-01 or higher. For more information about versioning headers, see Service Management Versioning.

The response includes an HTTP status code, a set of response headers, and a response body.

A successful operation returns status code 200 (OK). For information about status codes, see Service Management Status and Error Codes.

The response for this operation includes the following headers. The response may also include additional standard HTTP headers. All standard headers conform to the HTTP/1.1 protocol specification.

Response Header



A value that uniquely identifies a request made against the management service.

The format of the request body is as follows:

<?xml version="1.0" encoding="iso-8859-1"?>
<AvailabilityResponse xmlns="">

The following table describes the elements in the response body.

Element name



Indicates whether the DNS name is available for you to use.

Possible values are:

  • true

  • false

After you have verified the availability of the DNS name, you can create a profile using Create Profile. For more information about Azure Traffic Manager, see Azure Traffic Manager.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;
using System.Security.Cryptography.X509Certificates;
using System.Net;

namespace CheckDNSAvailability
  class Program
    private const string Thumbprint = "certificate-thumbprint";
    private const string SubscriptionId = "subscription-id";
    private const string Version = "2011-10-01";
    private const string DNSname = "";

    // Gets or sets the certificate that matches the Thumbprint value.
    private static X509Certificate2 Certificate { get; set; }

    static void Main(string[] args)
      Certificate = GetStoreCertificate(Thumbprint);
      // Create the uri and submit the request
      string uriFormat = "{0}/services/WATM/operations/isavailable/{1}";
      Uri uri = new Uri(String.Format(uriFormat, SubscriptionId, DNSname));
      XDocument responseBody;
      HttpWebResponse response = InvokeRequest(uri, "GET", out responseBody);

      // Get the response
      HttpStatusCode statusCode = statusCode = response.StatusCode;
      Console.WriteLine("The status of the operation: {0}\n\n", statusCode.ToString());
      Console.Write("Press any key to continue:");

    private static HttpWebResponse InvokeRequest(
      Uri uri,
      string method,
      out XDocument responseBody)
      HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
      request.Method = method;
      request.Headers.Add("x-ms-version", Version);
      request.ContentType = "application/xml";

      responseBody = null;
      HttpWebResponse response;

        response = (HttpWebResponse)request.GetResponse();
      catch (WebException ex)
        response = (HttpWebResponse)ex.Response;

      XmlReaderSettings settings = new XmlReaderSettings();
      settings.DtdProcessing = DtdProcessing.Ignore;

      if (response.ContentLength > 0)
        using (XmlReader reader = XmlReader.Create(response.GetResponseStream(), settings))
            responseBody = XDocument.Load(reader);
            responseBody = null;
      return response;

    private static X509Certificate2 GetStoreCertificate(string thumbprint)
      List<StoreLocation> locations = new List<StoreLocation>

      foreach (var location in locations)
        X509Store store = new X509Store("My", location);
          store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
          X509Certificate2Collection certificates = store.Certificates.Find(
          X509FindType.FindByThumbprint, thumbprint, false);
          if (certificates.Count == 1)
            return certificates[0];
      throw new ArgumentException(string.Format(
        "A Certificate with Thumbprint '{0}' could not be located.",