I have a .NET 2.0 client application that accesses a remoting endpoint hosted in IIS. The client is located on a network that has an authenticating proxy server. The client has the following code which it calls once when the app is started WebRequest.DefaultWebProxy.Credentials = new NetworkCredential(userName, password); The userName and password variables are initialized to the appropriate values before this call is made. The error I get is: System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. ---> System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure. at System.Net.Security.SslState.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, Exception exception) Based on the network trace file the root cause is: System.Net Information: 0 : [1652] SecureChannel#33145663 - Remote certificate has errors: System.Net Information: 0 : [1652] SecureChannel#33145663 - The revocation function was unable to check revocation for the certificate. System.Net Information: 0 : [1652] SecureChannel#33145663 - The revocation function was unable to check revocation because the revocation server was offline. The server certificate is issued by Entrust and is valid. The revocation server also appears to be online because calling the website through IE opens without any issue or warning. The network trace also shows that the proxy authentication negotiation is successful so the credentials are being sent and accepted by the proxy. System.Net Information: 0 : [1652] Connection#9040679 - Received status line: Version=1.1, StatusCode=407, StatusDescription=Proxy Authentication Required. ... System.Net Warning: 0 : [1652] HttpWebRequest#41364769::() - Resubmitting request. ... System.Net Information: 0 : [1652] ConnectStream#40550573 - Sending headers { Proxy-Authorization: Basic d2ViY29kaW5nOmFjY29yZGlz Host: mcx.precyse.net:443 }. System.Net.Sockets Verbose: 0 : [1652] Socket#53703870::Receive() System.Net.Sockets Verbose: 0 : [1652] Data from Socket#53703870::Receive System.Net.Sockets Verbose: 0 : [1652] 00000000 : 48 54 54 50 2F 31 2E 31-20 32 30 30 20 43 6F 6E : HTTP/1.1 200 Con System.Net.Sockets Verbose: 0 : [1652] 00000010 : 6E 65 63 74 69 6F 6E 20-65 73 74 61 62 6C 69 73 : nection establis System.Net.Sockets Verbose: 0 : [1652] 00000020 : 68 65 64 0D 0A 0D 0A : hed.... System.Net.Sockets Verbose: 0 : [1652] Exiting Socket#53703870::Receive() -> 39#39 System.Net Information: 0 : [1652] Connection#22896952 - Received status line: Version=1.1, StatusCode=200, StatusDescription=Connection established. But then once the actual POST is attempted the certificate revocation check fails. My guess is that the proxy credentials aren't being sent when the call to the revocation server is made internally by the framework. Any ideas?
