How do I remove domain.com/default.aspx?

Google has my home page indexed four times.

www.example.com/default.aspx
www.example.com/Default.aspx
example.com
www.example.com

I don't want to get a duplicate content penalty... does any one have any idea?

 

You need to sign up for Google Webmaster Tools. In the Webmaster Tools, there is a section where you can request URL removal. It will take a few days before Google removes URLs.

 

In order to do that, wouldn't I have to create a robot.txt file that blocks my default page from being indexed?

 

put 301 redirect.

 

I am using asp .net and it will put it in an infinite loop if I redirect default.aspx to /

 

ohh, I never use .net framework but In your other pages you can write code such as

private void Page_Load(object sender, System.EventArgs e)
{
Response.Status = "301 Moved Permanently";
Response.AddHeader("Location","http://www.example.com");
}

 

Right, that's exactly what I use for the other pages because I recently purchased an expired domain name. I am just having the problem with the default.aspx page.

 

Thanks every one. I found the answer. I have to use this tag:
<link rel="canonical" href="http://www.example.com/" />

in the head section to let google know which url is the one to use.