Remove "www" from domain by doing 301 redirect

  

Note: At first I thought it was a duplicate of How to redirect from non-www to www? but at I read that the question here is to remove the "www" and not add, in the other question I did not see examples of removing the "www" for this I am responding here.

I found two answers in SOen :

• Editing web.config ( redirectType="Permanent" indicates permanent redirect that is 301):

  <system.webServer>
      <rewrite>
          <rules>
              <rule name="Remove WWW prefix" >
                  <match url="(.*)" ignoreCase="true" />
                  <conditions>
                      <add input="{HTTP_HOST}" pattern="^www\.domain\.com" />
                  </conditions>
                  <action type="Redirect" url="http://domain.com/{R:1}" redirectType="Permanent" />
              </rule>
          </rules>
      </rewrite>
  </system.webServer>
  

  If you prefer to add www, change to:

              <add input="{HTTP_HOST}" pattern="^domain\.com" /> 
          </conditions> 
          <action type="Redirect" url="http://www.domain.com/{R:1}" redirectType="Permanent" /> 
      </rule> 
  

• Using the programming language, in this case an example with C #:

  protected void Application_BeginRequest(object sender, EventArgs e)
  {
     if (Request.Url.Host.StartsWith ("www") && !Request.Url.IsLoopback)
     {
        UriBuilder builder = new UriBuilder(Request.Url);
        builder.Host = Request.Url.Host.Replace("www.","");
        Response.StatusCode = 301;
        Response.AddHeader("Location", builder.ToString());
        Response.End();
     }
  }
  

  If you prefer to add www, change to:

  UriBuilder builder = new UriBuilder(Request.Url);
  builder.Host = "www." + Request.Url.Host;