iam using the following code to get the certificate from the server

Imports System.Net
Imports System.Net.Security
Imports System.Collections
Imports System.Security.Authentication
Imports System.Net.Sockets
Imports System.Text
Imports System.Security.Cryptography.X509Certificates
Imports System.IO
Module Module1
   Dim client As TcpClient
   Dim sslstream As SslStream
   Dim sender As New Object
   Dim certificate, servercertificate As New X509Certificate
   Dim chain As X509Chain
   Dim sslPolicyErrors As New SslPolicyErrors
   Dim expcerdate As New Date
   Dim certsubject, certname As String
   Dim certsubjectvalues() As String

   Sub Main(ByVal args() As String)

       'Dim st As NetworkStream = cli.
       Try
           client = New TcpClient
           client.Connect("winn.mygdc.com", 443)

       Catch ex As Exception
           'Console.WriteLine(ex.Message)
       End Try
       Console.WriteLine("Client is connected ")
       sslstream = New SslStream(client.GetStream(), False, New
RemoteCertificateValidationCallback(AddressOf
ValidateServerCertificate), Nothing)
       ' Try
       'sslstream = New SslStream(cli.OpenRead(args(0)), False, New
RemoteCertificateValidationCallback(AddressOf
ValidateServerCertificate), Nothing)
       'Catch ex As Exception
       'Console.WriteLine("Authentication Failed Closing Connection",
ex.Message)
       'End Try
       Try
           sslstream.AuthenticateAsClient("winn.mygdc.com")
       Catch ex As AuthenticationException
           Console.WriteLine("Authentication Failed Closing
Connection", ex.Message)

       End Try
       servercertificate = sslstream.RemoteCertificate()
       Console.WriteLine("Server certificate details...")
       Console.WriteLine(servercertificate.Issuer)
       Console.WriteLine(servercertificate.Subject)
       servercertificate.GetPublicKeyString()
       Console.WriteLine(servercertificate.GetEffectiveDateString())
       Console.WriteLine(servercertificate.GetExpirationDateString())
       Console.WriteLine(servercertificate.GetSerialNumberString())

Console.WriteLine(servercertificate.GetKeyAlgorithmParametersString())
       Console.WriteLine(servercertificate.GetType)
       certsubject = servercertificate.Subject
       certsubjectvalues = certsubject.Split(",")
       certname =
certsubjectvalues(0).Substring((certsubjectvalues(0).IndexOf("=") + 1))

       If (certname.Equals("winn.mygdc.com")) Then
           Console.WriteLine("Trusted certificate")
       Else
           Console.WriteLine("Untrusted certificate")
       End If
       expcerdate = CDate(servercertificate.GetExpirationDateString())

       If (Date.Now > expcerdate) Then
           Console.WriteLine("certificate expired")
       Else
           Console.WriteLine("certificate is valid")
       End If
       client.Close()
   End Sub
   Public Function ValidateServerCertificate(ByVal sender As Object,
ByVal certificate As X509Certificate, ByVal chain As X509Chain, ByVal
sslPolicyErrors As SslPolicyErrors) As Boolean

       If (sslPolicyErrors.Equals(sslPolicyErrors.None)) Then
           Return True
       Else
           Return False
       End If
   End Function
End Module

barathee_r...@yahoo.co.in wrote:

The first thing I would do is create an HttpWebRequest that attempts to
access your server and get the proxies working correctly by configuring the
Proxy property to work they way you need it to in your environment.

Once you can get the HttpWebRequest working and can get a response back,
then you can just add the ICertificatePolicy stuff.  Basically, you just
create a class that implements ICertificatePolicy, create an instance of it
and then set the CertificatePolicy property on the ServicePointManager to
the instance of your class.  Then, your CheckValidationResult method will be
called and the arguments of that function will contain the server
certificate.

You might also be able to get your SslStream approach to work by opening a
socket to the proxy server on the proxy server port, but I've never messed
with proxies at the TCP level before, so I don't know.

Joe K.