Mailkit 超时异常

Question

我正在开发一个小型应用程序，我必须在触发时使用 MailKit 发送电子邮件。我的开发环境是 Windows，生产环境是 Ubuntu 20.04 LTS。

在我的开发环境中，电子邮件发送成功，但是当在我的 linux 机器上部署相同的代码时，它显示

TimeoutException: The operation has timed out.

以下是异常日志；

MailKit.Net.SocketUtils.ConnectAsync(string host, int port, IPEndPoint localEndPoint, int timeout, bool doAsync, CancellationToken cancellationToken)
MailKit.MailService.ConnectSocket(string host, int port, bool doAsync, CancellationToken cancellationToken)
MailKit.Net.Smtp.SmtpClient.ConnectAsync(string host, int port, SecureSocketOptions options, bool doAsync, CancellationToken cancellationToken)
MailKit.Net.Smtp.SmtpClient.Connect(string host, int port, SecureSocketOptions options, CancellationToken cancellationToken)
MailKit.MailService.Connect(string host, int port, bool useSsl, CancellationToken cancellationToken)
XYZProject.Controllers.HomeController.TriggerException(string fileType) in D:\DotNet\DotNetCore\XYZProject\XYZProject\Controllers\HomeController.cs
XYZProject.Controllers.HomeController.Index(UploadFormViewModel model) in D:\DotNet\DotNetCore\XYZProject\XYZProject\Controllers\HomeController.cs
lambda_method35(Closure , object , object[] )
Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor+SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

这里要注意一点，为什么我在 linux 机器上得到我的 windows 路径。

这是我调用的用于发送电子邮件的函数；

private void TriggerException(string fileType)
{
    int port = Convert.ToInt32(_configuration["AlarmTrigger:Emails:Credentials:SmtpPort"]);
    string host = _configuration["AlarmTrigger:Emails:Credentials:SmtpServer"];
    string username = _configuration["AlarmTrigger:Emails:Credentials:User"];
    string password = _configuration["AlarmTrigger:Emails:Credentials:Password"];

    MailboxAddress mailFrom = new MailboxAddress(_configuration["AlarmTrigger:Emails:From:Name"],
        _configuration["AlarmTrigger:Emails:From:Email"]);

    MailboxAddress mailTo = new MailboxAddress(_configuration["AlarmTrigger:Emails:To:Name"], 
        _configuration["AlarmTrigger:Emails:To:Email"]);

    string mailTitle = "Failure Notification";
    string mailMessage = "Dear Team, \n\r" + fileType + " file upload failed.";

    var message = new MimeMessage();
    message.From.Add(mailFrom);
    message.ReplyTo.Add(mailFrom);
    message.To.Add(mailTo);
    message.Subject = mailTitle;
    message.Body = new TextPart("plain") { Text = mailMessage };

    using (var client = new SmtpClient())
    {
        //client.LocalDomain = "localhost";
        client.Connect(host, port, true);
        client.Authenticate(username, password);

        client.Send(message);
        client.Disconnect(true);
    }
}

Answer 1

你可以用这个。

                    MailMessage mail = new MailMessage();
                    SmtpClient SmtpServer = new SmtpClient("smtp.live.com");
                    mail.From = new MailAddress("username@hotmail.com");
                    mail.To.Add("Mail Adress");
                    mail.Subject = "Your Subject";
                    mail.Body = "This is for testing SMTP mail from GMAIL";
                    SmtpServer.Port = 587;
                    SmtpServer.Credentials = new System.Net.NetworkCredential("username@ghotmail.com", "Your PAssword");
                    SmtpServer.EnableSsl = true;
                    SmtpServer.Send(mail);

Answer 2

套接字在连接调用期间会出现超时异常if/when套接字无法在配置的时间跨度（默认情况下为 2）内在指定端口上连接到远程主机分钟）。

为了解决这个问题，您可以探索一些途径：

您可以尝试通过设置 SmtpClient.Timeout 值来增加超时。
确认您使用的是正确的主机名和端口。
确认您的生产环境没有阻止到您的程序试图通过防火墙或病毒扫描程序使用的端口上的邮件服务器的传出连接。
确认 ISP 或其他任何人没有通过他们的 防火墙阻止您的生产服务器的传出连接。
验证生产环境的路由表是否正确以及是否存在到 SMTP 服务器的有效网络路由。

Mailkit 超时异常

Mailkit Timeout Exception

c#

.net-core

mailkit