当 SmtpClient 工作时，SmtpAppender 无法通过 smtp-server 发送电子邮件

Question

我尝试在 LogNet 中使用 SmtpAppender：

<appender name="SmtpAppender" type="log4net.Appender.SmtpAppender">
      <to value="user1@company.com,user2@company.com" />
      <from value="noreply@company.com" />
      <subject value="Error" />
      <smtpHost value="smtp.company.com" />
      <bufferSize value="512" />
      <lossy value="true" />
      <evaluator type="log4net.Core.LevelEvaluator">
        <threshold value="DEBUG"/>
      </evaluator>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%newline%date [%thread] %-5level %logger [%property{NDC}] - %message%newline%newline%newline" />
      </layout>
    </appender>

当我在 Log4net 中启用调试日志记录时，我收到以下错误：

log4net:ERROR [SmtpAppender] ErrorCode: GenericFailure. Error occurred while sending e-mail notification. System.Net.Mail.SmtpException: Failure sending mail. ---> System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: An attempt was made to access a socket in a way forbidden by its access permissions (IP from SMTP-Server):25 at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception) --- End of inner exception stack trace --- at System.Net.ServicePoint.GetConnection(PooledStream PooledStream, Object owner, Boolean async, IPAddress& address,Socket& abortSocket, Socket& abortSocket6) at System.Net.PooledStream.Activate(Object owningObject, Boolean async, GeneralAsyncDelegate asyncCallback) at System.Net.PooledStream.Activate(Object owningObject, GeneralAsyncDelegate asyncCallback) at System.Net.ConnectionPool.GetConnection(Object owningObject, GeneralAsyncDelegate asyncCallback, Int32 creationTimeout) at System.Net.Mail.SmtpConnection.GetConnection(ServicePoint servicePoint) at System.Net.Mail.SmtpTransport.GetConnection(ServicePoint servicePoint) at System.Net.Mail.SmtpClient.GetConnection() at System.Net.Mail.SmtpClient.Send(MailMessage message) --- End of inner exception stack trace --- at System.Net.Mail.SmtpClient.Send(MailMessage message) at log4net.Appender.SmtpAppender.SendEmail(String messageBody) at log4net.Appender.SmtpAppender.SendBuffer(LoggingEvent[] events)

不过。当我尝试从使用此 log4net 配置的程序中通过同一 SMTP 服务器发送邮件时：

MailMessage msg = new MailMessage(sender, recipients, subject, body);
mtpClient client = new SmtpClient("smtp.company.com", 25);
client.Send(msg);

一切正常。所以这不可能是一个简单的 SMTP-Server/FireWall-Issue.

SMTPAppender 的工作方式是否与可能导致此问题的 .NET 标准 StmpClient.Send() 不同？

Answer 1

@Bob Geiger 指出了正确的方向，Log4net 似乎使用了完全相同的机制。

事实证明这是一个 Virusscan/Spam-Protection 问题。仅定义允许通过我们的 smtp 服务器发送邮件的应用程序。虽然我们中的一个程序使用与 log4net 相同的后端 - 应用程序使用不同的文件名，因此可以发送邮件，而另一个程序则不能。

我们必须在病毒扫描配置中允许特定的 .exe 文件。

当 SmtpClient 工作时，SmtpAppender 无法通过 smtp-server 发送电子邮件

SmtpAppender fails sending Emails through smtp-server while SmtpClient works

c#

log4net

smtp

smtpappender