System.Net.Mail.MailMessage“回复”标头在 IIS 6.0 中被忽略，但在 IIS 5.1 中正常

Question

我有一个在 WinXP 计算机 (IIS 5.1) 上开发和单元测试的 Web 应用程序项目。它已发布到Win2003Server (IIS 6.0)。该应用程序的一项功能会发送一封带有“回复”标题的电子邮件（下面是片段）。在 IIS 5.1 计算机上，回复正确显示在标头中。从 IIS 6.0 PC 发送时，标头不包含回复地址（见下文）：

    Public Shared Sub SendEmail_withReplyTo(ByVal emailfrom As String, _
                                        ByVal emailto As String, _
                                        ByVal vbody As String, _
                                        ByVal vsubject As String, _
                                        ByVal msgcc As String, _
                                        ByVal msgbcc As String, _
                                        ByVal sReplyTo As String)
    Dim MyMsg As New MailMessage
    ErrorTrap.ErrorMsg = Nothing
    With MyMsg
        .From = New MailAddress(emailfrom)
        .Headers.Add("Reply-To", sReplyTo)
        .To.Add(emailto)
        If msgcc.Length > 0 Then
            .CC.Add(msgcc)
        End If
        If msgbcc.Length > 0 Then
            .Bcc.Add(msgbcc)
        End If
        .Subject = vsubject
        .IsBodyHtml = True
        .Body = vbody
    End With
    Try
        Dim smtp As New SmtpClient
        smtp.Send(MyMsg)
    Catch ex As Exception
        ErrorTrap.ErrorMsg = Nothing
        ErrorTrap.ErrorMsg = ex.ToString
    End Try
End Sub

以下互联网标头是从 MS Outlook 2003 - 查看 - 选项粘贴的：

有效回复-从 JOHNXP 机器（带有 IIS 5.1 的开发 PC）发送的收件人：

Return-path: <[email protected]>
Received: from JohnXP (unverified [10.10.30.66]) by mail.cbmiweb.com
(Rockliffe SMTPRA 9.2.0) with ESMTP id <[email protected]>;
Mon, 28 Jun 2010 15:16:25 -0400
Message-ID: <[email protected]>
Reply-To: [email protected]
MIME-Version: 1.0
From: [email protected]
To: [email protected]
Date: 28 Jun 2010 15:17:57 -0400
Subject: Regarding your Ad #153949: Yard sale in vienna va June 12 at 8am
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: quoted-printable

缺少回复-从 MOJITO 机器（带有 IIS 6.0 的 2003 服务器）发送的收件人：

Return-path: <[email protected]>
Received: from MOJITO (unverified [10.10.30.14]) by mail.cbmiweb.com
(Rockliffe SMTPRA 9.2.0) with ESMTP id <[email protected]>;
Mon, 28 Jun 2010 13:37:53 -0400
Message-ID: <[email protected]>
MIME-Version: 1.0
From: [email protected]
To: [email protected]
Date: 28 Jun 2010 13:39:25 -0400
Subject: Regarding your Ad #153949: Yard sale in vienna va June 12 at 8am
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: quoted-printable

我什至设置了Win2003 计算机上的 VStudio2008 并在上面代码内的断点处停止，以确保邮件消息实际上已正确构建，并将“Reply-To”添加到标头（确实如此）。然而，当到达 Outlook 时，来自 MOJITO 服务器的邮件在标头中缺少“回复”。

是否存在其他配置问题会阻碍实际代码尝试执行的操作？

Answer 1

以下是我为解决此问题所做的更改：

Dim MyMsg As New MailMessage
With MyMsg
        .From = New MailAddress(emailfrom)
        .ReplyTo = New MailAddress(sReplyTo)    'new code that fixed the problem
        '.Headers.Add("Reply-To", sReplyTo)     'old code that works on WinXP IIS 5.1 

我从 Scott Mitchell 的这篇精彩文章中发现了这种替代编码方法：

"在 ASP.NET 2.0 中发送电子邮件：回复、优先级和已读回执"

似乎两种方法都应该有效，但现在是时候了继续前行。