https://github.com/cosullivan/SmtpServer

A SMTP Server component written in C#
https://github.com/cosullivan/SmtpServer

dotnet smtp smtp-server

Last synced: about 2 months ago
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A SMTP Server component written in C#

• Host: GitHub
• URL: https://github.com/cosullivan/SmtpServer
• Owner: cosullivan
• License: mit
• Created: 2016-01-16T03:05:39.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2024-01-18T09:36:35.000Z (8 months ago)
• Last Synced: 2024-06-21T18:11:44.928Z (3 months ago)
• Topics: dotnet, smtp, smtp-server
• Language: C#
• Size: 5.55 MB
• Stars: 672
• Watchers: 64
• Forks: 158
• Open Issues: 21
• Metadata Files:
  • Readme: README.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE

Awesome Lists containing this project

• awesome-dotnet-core - SmtpServer - Library to create your own SMTP server. (Frameworks, Libraries and Tools / Mail)
• awesome-dotnet-core - SmtpServer - 用于创建自己的SMTP服务器的库。 (框架, 库和工具 / 邮件)
• fucking-awesome-dotnet-core - SmtpServer - Library to create your own SMTP server. (Frameworks, Libraries and Tools / Mail)
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README

        
# What is SmtpServer?

[![NuGet](https://img.shields.io/nuget/v/SmtpServer.svg)](https://www.nuget.org/packages/SmtpServer/)

SmtpServer is a simple, but highly functional SMTP server implementation. Written entirely in C# it takes full advantage of the .NET TPL to achieve maximum performance.

SmtpServer is available via [NuGet](https://www.nuget.org/packages/SmtpServer/)

# Whats New?

See [here](https://github.com/cosullivan/SmtpServer/blob/master/Version8.md) for whats new in Version 8.

# What does it support?

SmtpServer currently supports the following ESMTP extensions:

- STARTTLS

- SIZE

- PIPELINING

- 8BITMIME

- AUTH PLAIN LOGIN

# How can it be used?

At its most basic, it only takes a few lines of code for the server to be listening to incoming requests.

```cs

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?

There are three hooks that can be implemented; IMessageStore, IMailboxFilter, and IUserAuthenticator.

```cs

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");

}

```

```cs

public class SampleMessageStore : MessageStore

{

    public override async Task SaveAsync(ISessionContext context, IMessageTransaction transaction, ReadOnlySequence 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;

        }

}

```

```cs

public class SampleMailboxFilter : IMailboxFilter, IMailboxFilterFactory

{

    public Task 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 CanDeliverToAsync(ISessionContext context, IMailbox to, IMailbox @from, CancellationToken token)

    {

        return Task.FromResult(MailboxFilterResult.Yes);

    }

    public IMailboxFilter CreateInstance(ISessionContext context)

    {

	return new SampleMailboxFilter();

    }

}

```

```cs

public class SampleUserAuthenticator : IUserAuthenticator, IUserAuthenticatorFactory

{

    public Task 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();

    }

}

```