The remote certificate is invalid error

Question

In my webpart i am trying to call url to get me xml but i am getting error

The remote certificate is invalid according to the validation procedure.
`WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.`

Here is how i am trying to access it

XmlDocument doc = new XmlDocument();
List<listXml> lt = new List<listXml>();
doc.Load("https://myexternalurl/list.xml");

I found this link but dont know where to put this in my webpart. It says to add this

ServicePointManager
.ServerCertificateValidationCallback += 
(sender, cert, chain, sslPolicyErrors) => true;

But i am not sure what to pass as sender,cert,chain,sslpolicyerrors. I want to avoid installing certificate on servers.

Answer 1

try this

ServicePointManager.ServerCertificateValidationCallback =
    delegate(object s, X509Certificate certificate,
             X509Chain chain, SslPolicyErrors sslPolicyErrors)
    { return true; };

Answer 2

Have you seen the another reply on the same link. He wrote a function for ignoring the bad certificate. Just call as is before your xml call.

//I use a method to ignore bad certs caused by misc errors
IgnoreBadCertificates();

// after the Ignore call i can do what ever i want...
HttpWebRequest request_data = System.Net.WebRequest.Create(urlquerystring) as HttpWebRequest;

/*
and below the Methods we are using...
*/

/// <summary>
/// Together with the AcceptAllCertifications method right
/// below this causes to bypass errors caused by SLL-Errors.
/// </summary>
public static void IgnoreBadCertificates()
{
    System.Net.ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(AcceptAllCertifications);
}  

/// <summary>
/// In Short: the Method solves the Problem of broken Certificates.
/// Sometime when requesting Data and the sending Webserverconnection
/// is based on a SSL Connection, an Error is caused by Servers whoes
/// Certificate(s) have Errors. Like when the Cert is out of date
/// and much more... So at this point when calling the method,
/// this behaviour is prevented
/// </summary>
/// <param name="sender"></param>
/// <param name="certification"></param>
/// <param name="chain"></param>
/// <param name="sslPolicyErrors"></param>
/// <returns>true</returns>
private static bool AcceptAllCertifications(object sender, System.Security.Cryptography.X509Certificates.X509Certificate certification, System.Security.Cryptography.X509Certificates.X509Chain chain, System.Net.Security.SslPolicyErrors sslPolicyErrors)
{
    return true;
} 

https://stackoverflow.com/questions/2675133/c-sharp-ignore-certificate-errors