.net - Authentication failed because remote party has closed the transport stream

Question

I am developing a TCP client to connect OpenSSL server with the certificate authentication. I have using .crt and .key files shared by server team. These certificates are generated by OpenSSL commands.

I am using SslStream object to authenticate the Tcp client by calling SslStream.AuthenticateAsClient method by passing server IP, SslProtocols.Ssl3 and X509CertificateCollection.

I am getting the following error:

Authentication failed because the remote party has closed the transport stream

Answer 1

I would advise against restricting the SecurityProtocol to TLS 1.1.

The recommended solution is to use

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls

Another option is add the following Registry key:

Key: HKEY_LOCAL_MACHINESOFTWAREMicrosoft.NETFrameworkv4.0.30319 
Value: SchUseStrongCrypto 

It is worth noting that .NET 4.6 will use the correct protocol by default and does not require either solution.