IMAP library SSL/TLS protocol versions

Question

What is the SSL protocol that IMAP library using? (e.g. SSL 2.0, SSL 3.0, TLS 1.0, or TLS 1.2)

What we found is that if we turned off SSL 2.0 and SSL 3.0, it no longer works?

Answer 1

It uses all that your .NET framework version support.

.NET 4.5 supports all of them: SSL 2.0, SSL 3.0, TLS 1.0, TLS 1.1, TLS 1.2.

You specify which security protocols are accepted using SSLConfiguration and EnabledSslProtocols properties:

using (Imap imap = new Imap())
{
    imap.SSLConfiguration.EnabledSslProtocols = 
        SslProtocols.Tls11 | SslProtocols.Tls12;
    imap.ConnectSSL("imap.example.com");

    imap.LoginPLAIN("user", "pass");

    // imap code goes here


    imap.Close();
}

Please note that both client and server must allow at least one shared protocol.