电子邮件地址中的撇号导致 SmtpException

Question

我们的业务应用程序为许多组织提供服务，其中一些组织的电子邮件地址（本地部分）中有撇号，这在技术上是有效的。

但是，如果 FROM 或 TO 电子邮件地址中包含撇号（本地部分），则根据此 C# 示例，我无法发送电子邮件：

    private const string SMTP_HOST = "localhost";
    public static void CreateCopyMessage2()
    {
//      var from = new MailAddress("john.o'connor@contoso.com", "John O'Connor");
        var from = new MailAddress("john.smith@contoso.com", "John Smith");

        var to = new MailAddress("jane.o'leary@contoso.com", "Jane O'Leary");
//      var to = new MailAddress("jane.smith@contoso.com", "Jane Smith");


        var message = new MailMessage(from, to) {
            Subject = "Email Subject",
            Body = "Email Body Text"
        };

        SmtpClient client = new SmtpClient(SMTP_HOST) {
            Credentials = CredentialCache.DefaultNetworkCredentials
        };

        try
        {
            client.Send(message);
        }
        catch (SmtpException ex)
        {
            Console.WriteLine($"Exception caught: {ex}");
        }
    }

to 电子邮件地址包含撇号时的异常详情：

System.Net.Mail.SmtpException: Syntax error in parameters or arguments. The server response was: Error in parameters. Syntax:{RCPT TO:<address> [SIZE=msgSize]}
   at System.Net.Mail.RecipientCommand.CheckResponse(SmtpStatusCode statusCode, String response)
   at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception)
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   at EmailWithApostropheTest.Program.Main() in ....\Program.cs:line 65

from 电子邮件地址包含撇号时的异常详情：

System.Net.Mail.SmtpException: Syntax error in parameters or arguments. The server response was: Error in parameters. Syntax:{MAIL FROM:<address> [SIZE=msgSize] [BODY=8BITMIME]}
   at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response)
   at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, MailAddress from, Boolean allowUnicode)
   at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception)
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   at EmailWithApostropheTest.Program.Main() in ....\Program.cs:line 65

电子邮件都可以不包含撇号。 任何建议将不胜感激。

编辑：@JamesThorpe 在下面评论了使用 telnet 进行测试。我有两个使用 hmailserver 和 mdaemon 的生产服务器和一个使用自己滚动的 smtp bin 的开发环境。这三个人都成功地接受和转发了包含撇号的电子邮件，而我自己滚动的电子邮件（在调试器中）在使用SMTPClient 时从未收到包含带有撇号的电子邮件地址的命令（MAIL FROM/RCPT TO），所以我确定这是 .NET SMTPClient 问题。

以下是有效的 telnet 示例（test.com 是我实际使用的占位符）：

220 test.com ESMTP Mon, 13 Nov 2017 17:30:29 +0000
HELO test.com
250 test.com Hello test.com [127.0.0.1], pleased to meet you
MAIL FROM:noreply.o'connor@myorg.com
250 2.1.0 Sender OK
RCPT TO:chris.walsh@real-sense.com
250 2.1.5 Recipient OK
DATA
354 Enter mail, end with <CRLF>.<CRLF>
test 123 test 123 from elms
.
250 2.6.0 Ok, message saved



220 test2.net ESMTP
HELO test2.net
250 Hello.
MAIL FROM:chris.walsh@test.net
250 OK
RCPT TO:john.o'connor@test.com
250 OK
DATA
354 OK, send.
Test 123
.
250 Queued (4.531 seconds)
MAIL FROM:test.o'connor@activbase.net
250 OK
RCPT TO:my.real.name@my.real.org.com
250 OK
DATA
354 OK, send.
test123
test 123
.
250 Queued (3.203 seconds)

谢谢， 克里斯。

Answer 1

如果您将交付格式设置为国际，它应该可以工作。类似的东西：

    SmtpClient client = new SmtpClient(SMTP_HOST) {
        Credentials = CredentialCache.DefaultNetworkCredentials,
        DeliveryFormat = SmtpDeliveryFormat.International
    };