I need to make a POST request using .Net. 

I can authenticate by GET, and so I’m trying to make a POST request on the same connection to keep my authentication.

The problem is I get a 401 Not Authenticated exception, which implies the connection hasn’t been reused. 

```
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");

request.GetResponse().Close();  // Works fine

// Now the request I want to make...

request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");

request.Method = "post";

string postData = "param1=1&param2=2";
byte[] data = new ASCIIEncoding().GetBytes(postData);
request.ContentLength = data.Length;
request.ContentType = "application/x-www-form-urlencoded";

using (Stream stream = request.GetRequestStream())
{
    stream.Write(data, 0, data.Length);
    stream.Close();
    request.GetResponse().Close();      // This line gets a 401 Not Authorized error.
}

```

EDIT: There has been some suggestions that I need to transfer cookies. The following doesn’t work either:

```
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");

var response = (HttpWebResponse)request.GetResponse();

var cookieContainer = new CookieContainer();
foreach (Cookie cookie in response.Cookies)
{
    cookieContainer.Add(cookie);
}

response.Close();

// Now the request I want to make...

request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");
request.CookieContainer = cookieContainer;

request.Method = "post";

string postData = "param1=1&param2=2";
byte[] data = new ASCIIEncoding().GetBytes(postData);
request.ContentLength = data.Length;
request.ContentType = "application/x-www-form-urlencoded";

using (Stream stream = request.GetRequestStream())
{
    stream.Write(data, 0, data.Length);
    request.GetResponse().Close();      // This line gets a 401 Not Authorized error.
}

```