Question

我看到一个奇怪的问题，而DKIM使用Mailkit＆amp; amp; Mimekit，Gmail报告错误＆＃34; dkim =中立（正文哈希未验证）＆＃34;。

我在这里做错了什么？。请在下面找到我的代码并截取实际收到的邮件的。

        string ReturnName = "DMC12";
        string FromDomain = "backtothefuture.net";
        string FromEmail = "marty@" + FromDomain;
        string FromName = "Marty McFly";
        string SenderName = "Marty McFly";
        string ToEmail = "George.mcfly.1960@gmail.com";
        string MailServer = "DMC12.large.timemachine.com";
        string TextBody = @"If you put your mind to it, you can accomplish anything. One other thing. If you guys ever have kids, and one of them, when he's eight years old, accidentally sets fire to the living room rug... go easy on him!";
        string HtmlBody = string.Format(@"<b>如果你把你的头脑，它可以完成任何事情。 另一件事。 如果你们有孩子，其中一个，当他八岁时，不小心把火烧在客厅地毯上...去容易对他！</b>");
        string Subject  = "Message from Marty (1960)!";
        string ToName = "George McFly";
        string DKIMdomain = FromDomain;
        string DKIMSigner = "btfreturns.com";         
        string ReturnEmail = "DocBrown@" + MailServer;
        string SenderEmail = "marty@" + MailServer;
        string privatekey = System.IO.File.ReadAllText("dkim.private.key");
        var client = new SmtpClient(new ProtocolLogger("smtp.txt")); // logging SMTP connections

            try
            {
                client.Connect(MailServer, 25);
            }
            catch (SmtpCommandException ex)
            {
                Console.WriteLine("Error trying to connect: {0}", ex.Message);
                Console.WriteLine("\tStatusCode: {0}", ex.StatusCode);
                return;
            }
            catch (SmtpProtocolException ex)
            {
                Console.WriteLine("Protocol error while trying to connect: {0}", ex.Message);
                return;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                return;
            }   

            client.LocalDomain = MailServer;

            var message = new MimeMessage();
            MailboxAddress RecepientAddress = new MailboxAddress(ToName, ToEmail);

            message.From.Add(new MailboxAddress(FromName, FromEmail)); // From Address
            var builder = new BodyBuilder();

            builder.TextBody = TextBody;
            builder.HtmlBody = HtmlBody;

            List<MailboxAddress> To = new List<MailboxAddress>();
            To.Add(RecepientAddress);

            message.Subject = Subject;
            message.Body = builder.ToMessageBody();
            message.Sender = new MailboxAddress(SenderName, SenderEmail);  // Sender Address
            message.To.Add(RecepientAddress);       
            message.MessageId = Guid.NewGuid().ToString("N") + "@" + new System.Net.Mail.MailAddress(message.Sender.Address).Host;


                using (Stream s = (new MemoryStream(Encoding.UTF8.GetBytes(privatekey ?? ""))))
                {
                    var headersToSign = new[] { HeaderId.From, HeaderId.To, HeaderId.Subject, HeaderId.Date, HeaderId.MessageId };
                    var signer = new DkimSigner(s, DKIMdomain, DKIMSigner);
                    signer.SignatureAlgorithm = DkimSignatureAlgorithm.RsaSha1;
                    message.Sign(signer, headersToSign, DkimCanonicalizationAlgorithm.Relaxed, DkimCanonicalizationAlgorithm.Relaxed);
                }


                client.Send(message, new MailboxAddress(ReturnName, ReturnEmail), To);              
                client.Disconnect(true);
                client.Connect(MailServer, 25);
                client.Dispose();

Answer 1

问题是您在DKIM签名邮件之前没有呼叫message.Prepare()。这是非常重要的一步，因为它强制将邮件正文的所有MIME部分转换为适当的编码以用于传输。

请注意，如果您没有使用适当的编码约束值调用Prepare()，那么SmtpClient.Send()方法将在 DKIM签名邮件之后 从而使签名无效。

我的建议是使用EncodingConstraint.SevenBit来实现最大的互操作性。

但是，如果您知道您的SMTP服务器和您的邮件将通过8BITMIME扩展程序传输的所有其他SMTP服务器，那么您可以尝试使用EncodingConstraint.EightBit。

DKIM签名失败，身体哈希没有验证Mimekit 1.10.1.0，Mailkit 1.10.2.0

1 个答案: