What is SmtpServer?

🆕 What's New?

⚡ Supported ESMTP Extensions

Installation

PM> install-package SmtpServer

🚀 Getting Started

var options = new SmtpServerOptionsBuilder()
 .ServerName("localhost")
 .Port(25, 587)
 .Build();
var smtpServer = new SmtpServer.SmtpServer(options, ServiceProvider.Default);
await smtpServer.StartAsync(CancellationToken.None);

What hooks are provided?

var options = new SmtpServerOptionsBuilder()
 .ServerName("localhost")
 .Endpoint(builder =>
 builder
 .Port(9025, true)
 .AllowUnsecureAuthentication(false)
 .Certificate(CreateCertificate()))
 .Build();
var serviceProvider = new ServiceProvider();
serviceProvider.Add(new SampleMessageStore());
serviceProvider.Add(new SampleMailboxFilter());
serviceProvider.Add(new SampleUserAuthenticator());
var smtpServer = new SmtpServer.SmtpServer(options, serviceProvider);
await smtpServer.StartAsync(CancellationToken.None);
// to create an X509Certificate for testing you need to run MAKECERT.EXE and then PVK2PFX.EXE
// http://www.digitallycreated.net/Blog/38/using-makecert-to-create-certificates-for-development
static X509Certificate2 CreateCertificate()
{
 var certificate = File.ReadAllBytes(@"Certificate.pfx");
 return new X509Certificate2(certificate, "P@ssw0rd");
}

public class SampleMessageStore : MessageStore
{
 public override async Task<SmtpResponse> SaveAsync(ISessionContext context, IMessageTransaction transaction, ReadOnlySequence<byte> buffer, CancellationToken cancellationToken)
 {
 await using var stream = new MemoryStream();
 var position = buffer.GetPosition(0);
 while (buffer.TryGet(ref position, out var memory))
 {
 await stream.WriteAsync(memory, cancellationToken);
 }
 stream.Position = 0;
 var message = await MimeKit.MimeMessage.LoadAsync(stream, cancellationToken);
 Console.WriteLine(message.TextBody);
 return SmtpResponse.Ok;
 }
}

public class SampleMailboxFilter : IMailboxFilter, IMailboxFilterFactory
{
 public Task<MailboxFilterResult> CanAcceptFromAsync(ISessionContext context, IMailbox @from, int size, CancellationToken cancellationToken)
 {
 if (String.Equals(@from.Host, "test.com"))
 {
 return Task.FromResult(MailboxFilterResult.Yes);
 }
 return Task.FromResult(MailboxFilterResult.NoPermanently);
 }
 public Task<MailboxFilterResult> CanDeliverToAsync(ISessionContext context, IMailbox to, IMailbox @from, CancellationToken token)
 {
 return Task.FromResult(MailboxFilterResult.Yes);
 }
 public IMailboxFilter CreateInstance(ISessionContext context)
 {
 return new SampleMailboxFilter();
 }
}

public class SampleUserAuthenticator : IUserAuthenticator, IUserAuthenticatorFactory
{
 public Task<bool> AuthenticateAsync(ISessionContext context, string user, string password, CancellationToken token)
 {
 Console.WriteLine("User={0} Password={1}", user, password);
 return Task.FromResult(user.Length > 4);
 }
 public IUserAuthenticator CreateInstance(ISessionContext context)
 {
 return new SampleUserAuthenticator();
 }
}