如何验证指定的SMTP服务器，端口，用户名和密码有效或存在(使用.net语言)? [英] How to validate the specified SMTP server,port,username and password is effective or exist(use .net language)?

问题描述

How to validate the specified SMTP server,port,username and password is effective or exist(use .net language)?
For example:
smtp.mail.yahoo.com(SMTPserver),465(port),[e-mail](username),hb33qtm(password)
If this account is effective or  exist ,return true(Can include a return message better),orelse return false.
My code:
 ''' <summary>
    ''' validate the specified SMTP server,port,username and password is effective or exist
    ''' </summary>
    ''' <param name="_server">smtp server</param>
    ''' <param name="_port">smtp port</param>
    ''' <param name="_email">Email Account</param>
    ''' <param name="_pass">Email pwd</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Function ValiateEmail(ByVal _server As String, ByVal _port As String, ByVal _email As String, ByVal _pass As String) As String

        Try
            Dim str As String = ""
            Dim tcpc As New TcpClient()
            tcpc.SendTimeout = 3000
            tcpc.Connect(_server, _port)
            Dim sr As New StreamReader(tcpc.GetStream(), Encoding.Default)
            Str = sr.ReadLine()
            If CInt(Str.Substring(0, 3)) <> 220 Then
                SenSmtpCmd(tcpc, "QUIT")
                Return 0 & vbTab & "SMTP server does not exist"
            End If
            Str = SenSmtpCmd(tcpc, "EHLO " & _server)
            If CInt(Str.Substring(0, 3)) <> 250 Then
                SenSmtpCmd(tcpc, "QUIT")
                Return 0 & vbTab & "EHLO Command not complete, the port may not provide SMTP service"
            End If
            str = SenSmtpCmd(tcpc, "AUTH LOGIN")
            MsgBox(str) 'Return 334，it's ok
            str = SenSmtpCmd(tcpc, Convert.ToBase64String(Encoding.Default.GetBytes(_email)))
            MsgBox(str) 'Return null,Why is there an empty value
            str = SenSmtpCmd(tcpc, Convert.ToBase64String(Encoding.Default.GetBytes(_pass)))
            MsgBox(str)
            If CInt(Str.Substring(0, 3)) <> 235 Then
                SenSmtpCmd(tcpc, "QUIT")
                Return 0 & vbTab & "User name or password is incorrect"
            End If
            SenSmtpCmd(tcpc, "QUIT")
            Return 1 & vbTab & "Effective"
        Catch ex As Exception
            Return 0 & vbTab & ex.Message
        End Try
    End Function

 Private Function SenSmtpCmd(ByVal tcpc As TcpClient, ByVal strCmd As String) As String
        Dim arrCmd As Byte()
        Dim stateRet As String
        Dim sr As StreamReader
        Dim s As Stream
        s = tcpc.GetStream() 'Sometimes,get null value,why???
        strCmd = strCmd & vbCr & vbLf
        arrCmd = Encoding.[Default].GetBytes(strCmd.ToCharArray())
        s.Write(arrCmd, 0, strCmd.Length)
        s.Flush()
        sr = New StreamReader(tcpc.GetStream(), Encoding.Default)
        stateRet = sr.ReadLine() '
        Return stateRet
    End Function

VB 2005,Help!

推荐答案

如何验证指定的SMTP服务器，端口，用户名和密码有效或存在
对于SMTP服务器，端口:
如果使用公司服务器，则需要与IT管理员联系.
如果使用第三方服务器，则需要查看第三方的电子邮件配置.例如:GMail，Yahoo等.

对于用户名，密码:
您应该自己使用电子邮件功能.从管理员那里获取或在第三方站点进行注册.

How to validate the specified SMTP server,port,username and password is effective or exist
For SMTP server, Port:
You need to talk to your IT admin for it if you are using a company server.
You need to look at the email configuration of third party if you are using their server. example: GMail, Yahoo, etc.

For Username, Password:
You should have one for yourself to use the email facility. Get from your admin or register at third part site for it.

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