C# – .Net Remoting vs. WCF

Here's another vote for JMeter.

JMeter is an open-source load testing tool, written in Java. It's capable of testing a number of different server types (for example, web, web services, database, just about anything that uses requests basically).

It does however have a steep learning curve once you start getting to complicated tests, but it's well worth it. You can get up and running very quickly, and depending on what sort of stress-testing you want to do, that might be fine.

Pros:

• Open-Source/Free tool from the Apache project (helps with buy-in)
• Easy to get started with, and easy to use once you grasp the core concepts. (Ie, how to create a request, how to create an assertion, how to work with variables etc).
• Very scalable. I've run tests with 11 machines generating load on the server to the tune of almost a million hits/hour. It was much easier to setup than I was expecting.
• Has an active community and good resources to help you get up and running. Read the tutorials first and play with it for a while.

Cons:

• The UI is written in Swing. (ugh!)
• JMeter works by parsing the response text returned by the server. So if you're looking to validate any sort of javascript behaviours, you're out of luck.
• Learning curve is steep for non-programmers. If you're familiar with regular expressions, you're already ahead of the game.
• There are large numbers of (insert expletive) idiots in the support forum asking stupid questions that could be easily solved if they'd give the documentation even a cursory glance. ('How do I use JMeter to stress-test my Windows GUI' shows up quite frequently).
• Reporting 'out of the box' leaves much to be desired, particularly for larger tests. In the test I mentioned above, I ended up having to write a quick console app to do some of the 'xml-logfile' to 'html' conversions. That was a few years ago though, so it's probable that this would no longer be required.

Be sure to use System.Net.Mail, not the deprecated System.Web.Mail. Doing SSL with System.Web.Mail is a gross mess of hacky extensions.

using System.Net;
using System.Net.Mail;

var fromAddress = new MailAddress("from@gmail.com", "From Name");
var toAddress = new MailAddress("to@example.com", "To Name");
const string fromPassword = "fromPassword";
const string subject = "Subject";
const string body = "Body";

var smtp = new SmtpClient
{
    Host = "smtp.gmail.com",
    Port = 587,
    EnableSsl = true,
    DeliveryMethod = SmtpDeliveryMethod.Network,
    UseDefaultCredentials = false,
    Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
};
using (var message = new MailMessage(fromAddress, toAddress)
{
    Subject = subject,
    Body = body
})
{
    smtp.Send(message);
}

Additionally go to the Google Account > Security page and look at the Signing in to Google > 2-Step Verification setting.

• If it is enabled, then you have to generate a password allowing .NET to bypass the 2-Step Verification. To do this, click on Signing in to Google > App passwords, select app = Mail, and device = Windows Computer, and finally generate the password. Use the generated password in the fromPassword constant instead of your standard Gmail password.
• If it is disabled, then you have to turn on Less secure app access, which is not recommended! So better enable the 2-Step verification.