Retrieving modified date from a URL. (Ensuring the connection is closed).

[Tao]

I'm using the following code in my service to retrieve the modified date of
a web page.

public DateTime GetUrlSourceLastModified(string sUri)
{
if(!sUri.ToLower().StartsWith("http://"))
sUri = "http://" + sUri;
Uri uriObj = new Uri(sUri);
HttpWebRequest request =
(HttpWebRequest)WebRequest.CreateDefault(uriObj);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
DateTime d = response.LastModified;
response = null;
request = null;
return d;
}

The code above works, however I've noticed via monitoring my firewall that
when this code finishes the connection isn't closed. In fact it appears to
stay connected for a long period of time / indefinitely. How can I ensure
the connection is closed when leaving this procedure.

Any advise appreciated.

Tao