Question

我的SMTP代码适用于Gmail，但是当我在Yahoo和Hotmail上试用它时总是会失败。我已经输入了正确的服务器和端口，但它仍然不允许我发送。我真的很困惑我在哪里出错了，因为我能够在gmail下完美地发送邮件。

这是我的完整代码：

Function SendEmail(ByVal Recipients As List(Of String), _
                  ByVal FromAddress As String, _
                  ByVal Subject As String, _
                  ByVal Body As String, _
                  ByVal UserName As String, _
                  ByVal Password As String, _
                  Optional ByVal Server As String, _
                  Optional ByVal Port As Integer, _
                  Optional ByVal Attachments As List(Of String) = Nothing) As String


    Dim Email As New MailMessage()
    Try
        Dim SMTPServer As New SmtpClient
        For Each Attachment As String In Attachments
            Email.Attachments.Add(New Attachment(Attachment))
        Next
        Email.From = New MailAddress(FromAddress)
        For Each Recipient As String In Recipients
            Email.To.Add(Recipient)
        Next
        Email.Subject = Subject
        Email.Body = Body
        SMTPServer.Host = Server
        SMTPServer.Port = Port
        SMTPServer.Credentials = New System.Net.NetworkCredential(UserName, Password)
        SMTPServer.EnableSsl = True
        SMTPServer.Send(Email)
        SMTPServer.Timeout = 500
        Email.Dispose()

        Return "Email to " & Recipients(0) & " from " & FromAddress & " was sent."
    Catch ex As SmtpException
        Email.Dispose()
        Return "Sending Email Failed. Smtp Error."
    Catch ex As ArgumentOutOfRangeException
        Email.Dispose()
        Return "Sending Email Failed. Check Port Number."
    Catch Ex As InvalidOperationException
        Email.Dispose()
        Return "Sending Email Failed. Check Port Number."
    End Try
End Function


    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim Recipients As New List(Of String)
    Recipients.Add("put recipient email here")
    Dim FromEmailAddress As String = Recipients(0)
    Dim Subject As String = "subject goes here"
    Dim Body As String = "Email body goes here"
    Dim UserName As String = "put username here"
    Dim Password As String = "put password here"
    Dim Port As Integer = port number goes here
    Dim Server As String = "SMTP server goes here"
    Dim Attachments As New List(Of String)
    MsgBox(SendEmail(Recipients, FromEmailAddress, Subject, Body, UserName, Password, Server, Port, Attachments))

End Sub

与Gmail相比，Yahoo和Hotmail的行为有何不同？我对这个SMTP事情真的很陌生。我刚开始学习今天请耐心等待。任何建议或意见都将被接受。提前谢谢。

Answer 1

他们在不同的端口工作：

Hotmail外发邮件服务器（SMTP） - smtp.live.com（已启用TLS，端口587）

Yahoo外发邮件服务器（SMTP） - smtp.mail.yahoo.com（启用SSL，端口995）

确保您使用的是：

SMTPServer.EnableSsl = True

并更改每项服务的SMTP端口。（在这种情况下，Hotmail为587）。

一个是SSL，另一个是TLS。 TLS（传输级别安全性）是一个稍微宽泛的术语，已取代SSL，所以不用担心，它可以使用EnableSsl

Answer 2

您可以将EASendMail库用于.NET，它会自动检测端口。

http://www.emailarchitect.net/easendmail/

示例我做了：

   Private Function Hotmail_Sender(ByVal Account_User As String, ByVal Account_Password As String, ByVal Mail_To As String, ByVal Mail_Subject As String, ByVal Mail_Body As String, Optional ByVal Mail_Attachments() As String = Nothing) As Boolean

       Dim Hot_Mail As New EASendMail.SmtpMail("TryIt")
       Dim Hot_Server As New EASendMail.SmtpServer("smtp.live.com")
       Dim Hot_Smtp As New EASendMail.SmtpClient()

       Hot_Server.User = Account_User
       Hot_Server.Password = Account_Password
       Hot_Server.ConnectType = EASendMail.SmtpConnectType.ConnectSSLAuto

       Hot_Mail.From = Account_User
       Hot_Mail.To = Mail_To
       Hot_Mail.Subject = Mail_Subject
       Hot_Mail.TextBody = Mail_Body
       If Mail_Attachments IsNot Nothing Then For Each Attachment In Mail_Attachments : Hot_Mail.AddAttachment(Attachment) : Next

       Try : Hot_Smtp.SendMail(Hot_Server, Hot_Mail) : Return True
       Catch ex As Exception : Return False : End Try

   End Function

Yahoo和Hotmail上的SMTP发送失败

2 个答案: