C# ASP.NET Send Email via TLS

Question

In order to comply with HIPAA regulations, we need to send email from an external site (outside the firewall) to an internal Exchange server (inside the firewall). Our Exchange admins tell us we need to use TLS encryption to send mail from the web server to the email server.

I've never used TLS before and I'm not very familiar with it. Searching on Google as brought up numerous paid-for-use libraries. Is there anything native to .NET that will accomplish this? If so, how do I configure it? If not, is there something free or open source?

Current Configuration: ASP.NET C# Web Application 2.0 Framework Using System.Net.Mail to send email and attachments via SMTP IIS 6.0

Answer 1

TLS (Transport Level Security) is the slightly broader term that has replaced SSL (Secure Sockets Layer) in securing HTTP communications. So what you are being asked to do is enable SSL.

Answer 2

On SmtpClient there is an EnableSsl property that you would set.

i.e.

SmtpClient client = new SmtpClient(exchangeServer);
client.EnableSsl = true;
client.Send(msg);