我使用 MailEnable 通过 mailhost 从我的 Windows Server 2016 VPS 发送电子邮件localhost。使用此代码一切正常：
Dim mailObj As New SmtpClient
mailObj.Host = "localhost"
mailObj.Port = 25
但是，当我尝试通过 SSL 发送电子邮件时，出现错误：
服务器不支持安全连接。
- 我在 Windows 防火墙中打开了 SMTP 端口 587
- 我获得了域名的 SSL 证书并分配给 MailEnable：example.com、www.example.com、smtp.example.com、mail.example.com、ftp.example.com、pop.example.com
- 配置MailEnable，也使用上面的证书
我的后端代码：
Dim mailObj As New SmtpClient
mailObj.Host = "localhost"
mailObj.EnableSsl = True
mailObj.Port = 587
mailObj.UseDefaultCredentials = false
mailObj.Credentials = New System.Net.NetworkCredential("[email protected]", "mypwd")
当我检查Enable TLS下面的第一个屏幕截图时出现错误：
邮件发送失败。
这是我启用后获得的日志Enable TLS：
[06/23/20 22:33:31]****************** LOG FILE STARTED *******************
06/23/20 22:33:31 SMTP-IN A4C36F71EB8A4F0C8708CD88F4DF3671.MAI 1020 212.60.249.12 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:31 0 0
06/23/20 22:33:32 SMTP-IN FFD462EEB67B44159FF086464B9D3C5E.MAI 1036 212.70.149.50 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:32 0 0
06/23/20 22:33:33 SMTP-IN BDFF4AEDD8B94D0987166BA0DEAC1FC0.MAI 1060 185.143.72.34 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:33 0 0
06/23/20 22:33:33 SMTP-IN A4C36F71EB8A4F0C8708CD88F4DF3671.MAI 1020 212.60.249.12 EHLO EHLO User 250-example.com [212.60.249.12], this server offers 5 extensions 143 11
06/23/20 22:33:34 SMTP-IN FFD462EEB67B44159FF086464B9D3C5E.MAI 1036 212.70.149.50 EHLO EHLO User 250-example.com [212.70.149.50], this server offers 5 extensions 143 11
06/23/20 22:33:34 SMTP-IN BDFF4AEDD8B94D0987166BA0DEAC1FC0.MAI 1060 185.143.72.34 EHLO EHLO User 250-example.com [185.143.72.34], this server offers 5 extensions 143 11
06/23/20 22:33:34 SMTP-IN A4C36F71EB8A4F0C8708CD88F4DF3671.MAI 1020 212.60.249.12 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:35 SMTP-IN FFD462EEB67B44159FF086464B9D3C5E.MAI 1036 212.70.149.50 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:35 SMTP-IN BDFF4AEDD8B94D0987166BA0DEAC1FC0.MAI 1060 185.143.72.34 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:36 SMTP-IN A4C36F71EB8A4F0C8708CD88F4DF3671.MAI 1020 212.60.249.12 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:37 SMTP-IN BDFF4AEDD8B94D0987166BA0DEAC1FC0.MAI 1060 185.143.72.34 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:37 SMTP-IN FFD462EEB67B44159FF086464B9D3C5E.MAI 1036 212.70.149.50 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:37 SMTP-IN D50DB0BE07584F9484734E4E911EE303.MAI 1104 185.143.75.153 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:37 0 0
06/23/20 22:33:37 SMTP-IN A4C36F71EB8A4F0C8708CD88F4DF3671.MAI 1020 212.60.249.12 AUTH {blank} 334 UGFzc3dvcmQ6 18 30 [email protected]
06/23/20 22:33:38 SMTP-IN D50DB0BE07584F9484734E4E911EE303.MAI 1104 185.143.75.153 EHLO EHLO User 250-example.com [185.143.75.153], this server offers 5 extensions 144 11
06/23/20 22:33:38 SMTP-IN BDFF4AEDD8B94D0987166BA0DEAC1FC0.MAI 1060 185.143.72.34 AUTH {blank} 334 UGFzc3dvcmQ6 18 30 [email protected]
06/23/20 22:33:38 SMTP-IN 09B37BA353F34F3EA5A98E682F9E963C.MAI 1120 212.70.149.18 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:38 0 0
06/23/20 22:33:38 SMTP-IN FFD462EEB67B44159FF086464B9D3C5E.MAI 1036 212.70.149.50 AUTH {blank} 334 UGFzc3dvcmQ6 18 30 [email protected]
06/23/20 22:33:39 SMTP-IN D50DB0BE07584F9484734E4E911EE303.MAI 1104 185.143.75.153 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:39 SMTP-IN A4C36F71EB8A4F0C8708CD88F4DF3671.MAI 1020 212.60.249.12 AUTH bGV0bWVpbg== 504 Invalid Username or Password 34 14 [email protected]
06/23/20 22:33:39 SMTP-IN BDFF4AEDD8B94D0987166BA0DEAC1FC0.MAI 1060 185.143.72.34 AUTH Rk9VUklFUg== 504 Invalid Username or Password 34 14 [email protected]
06/23/20 22:33:39 SMTP-IN 09B37BA353F34F3EA5A98E682F9E963C.MAI 1120 212.70.149.18 EHLO EHLO User 250-example.com [212.70.149.18], this server offers 5 extensions 143 11
06/23/20 22:33:40 SMTP-IN D50DB0BE07584F9484734E4E911EE303.MAI 1104 185.143.75.153 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:40 SMTP-IN FFD462EEB67B44159FF086464B9D3C5E.MAI 1036 212.70.149.50 AUTH UEBzc3cwcmQ= 504 Invalid Username or Password 34 14 [email protected]
06/23/20 22:33:40 SMTP-IN 09B37BA353F34F3EA5A98E682F9E963C.MAI 1120 212.70.149.18 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:40 SMTP-IN 09B37BA353F34F3EA5A98E682F9E963C.MAI 1120 212.70.149.18 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:40 SMTP-IN BDFF4AEDD8B94D0987166BA0DEAC1FC0.MAI 1060 185.143.72.34 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:33:40 SMTP-IN A4C36F71EB8A4F0C8708CD88F4DF3671.MAI 1020 212.60.249.12 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:33:41 SMTP-IN D50DB0BE07584F9484734E4E911EE303.MAI 1104 185.143.75.153 AUTH {blank} 334 UGFzc3dvcmQ6 18 26 [email protected]
06/23/20 22:33:41 SMTP-IN 09B37BA353F34F3EA5A98E682F9E963C.MAI 1120 212.70.149.18 AUTH {blank} 334 UGFzc3dvcmQ6 18 30 [email protected]
06/23/20 22:33:41 SMTP-IN FFD462EEB67B44159FF086464B9D3C5E.MAI 1036 212.70.149.50 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:33:42 SMTP-IN D50DB0BE07584F9484734E4E911EE303.MAI 1104 185.143.75.153 AUTH MTExMQ== 504 Invalid Username or Password 34 10 [email protected]
06/23/20 22:33:42 SMTP-IN 09B37BA353F34F3EA5A98E682F9E963C.MAI 1120 212.70.149.18 AUTH bXl0aW1lMDE= 504 Invalid Username or Password 34 14 [email protected]
06/23/20 22:33:43 SMTP-IN D50DB0BE07584F9484734E4E911EE303.MAI 1104 185.143.75.153 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:33:43 SMTP-IN 09B37BA353F34F3EA5A98E682F9E963C.MAI 1120 212.70.149.18 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:33:45 SMTP-IN CA6566ED0D5C4CF4BC9EA6A1A5AC988B.MAI 1068 185.143.75.81 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:45 0 0
06/23/20 22:33:46 SMTP-IN CA6566ED0D5C4CF4BC9EA6A1A5AC988B.MAI 1068 185.143.75.81 EHLO EHLO User 250-example.com [185.143.75.81], this server offers 5 extensions 143 11
06/23/20 22:33:47 SMTP-IN CA6566ED0D5C4CF4BC9EA6A1A5AC988B.MAI 1068 185.143.75.81 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:48 SMTP-IN CA6566ED0D5C4CF4BC9EA6A1A5AC988B.MAI 1068 185.143.75.81 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:49 SMTP-IN CA6566ED0D5C4CF4BC9EA6A1A5AC988B.MAI 1068 185.143.75.81 AUTH {blank} 334 UGFzc3dvcmQ6 18 38 [email protected]
06/23/20 22:33:50 SMTP-IN CB468621E3BC48089B6A50F14530F7F9.MAI 1136 212.70.149.2 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:50 0 0
06/23/20 22:33:50 SMTP-IN CA6566ED0D5C4CF4BC9EA6A1A5AC988B.MAI 1068 185.143.75.81 AUTH cEBzc3cwcmQ= 504 Invalid Username or Password 34 14 [email protected]
06/23/20 22:33:51 SMTP-IN CB468621E3BC48089B6A50F14530F7F9.MAI 1136 212.70.149.2 EHLO EHLO User 250-example.com [212.70.149.2], this server offers 5 extensions 142 11
06/23/20 22:33:51 SMTP-IN CA6566ED0D5C4CF4BC9EA6A1A5AC988B.MAI 1068 185.143.75.81 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:33:52 SMTP-IN CB468621E3BC48089B6A50F14530F7F9.MAI 1136 212.70.149.2 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:53 SMTP-IN CB468621E3BC48089B6A50F14530F7F9.MAI 1136 212.70.149.2 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:54 SMTP-IN B4699D1493B74E85A8671850B09F08D3.MAI 1112 185.143.72.25 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:33:54 0 0
06/23/20 22:33:54 SMTP-IN CB468621E3BC48089B6A50F14530F7F9.MAI 1136 212.70.149.2 AUTH {blank} 334 UGFzc3dvcmQ6 18 34 [email protected]
06/23/20 22:33:55 SMTP-IN CB468621E3BC48089B6A50F14530F7F9.MAI 1136 212.70.149.2 AUTH ZWRhbWFtdXI= 504 Invalid Username or Password 34 14 [email protected]
06/23/20 22:33:55 SMTP-IN B4699D1493B74E85A8671850B09F08D3.MAI 1112 185.143.72.25 EHLO EHLO User 250-example.com [185.143.72.25], this server offers 5 extensions 143 11
06/23/20 22:33:56 SMTP-IN CB468621E3BC48089B6A50F14530F7F9.MAI 1136 212.70.149.2 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:33:56 SMTP-IN B4699D1493B74E85A8671850B09F08D3.MAI 1112 185.143.72.25 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:33:58 SMTP-IN B4699D1493B74E85A8671850B09F08D3.MAI 1112 185.143.72.25 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:33:59 SMTP-IN B4699D1493B74E85A8671850B09F08D3.MAI 1112 185.143.72.25 AUTH {blank} 334 UGFzc3dvcmQ6 18 26 [email protected]
06/23/20 22:34:00 SMTP-IN B4699D1493B74E85A8671850B09F08D3.MAI 1112 185.143.72.25 AUTH MTIzNDU2Nzg= 504 Invalid Username or Password 34 14 [email protected]
06/23/20 22:34:01 SMTP-IN 9CBF0EE9385B47DE8E869EAFE6CC220D.MAI 1100 212.70.149.50 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:34:01 0 0
06/23/20 22:34:01 SMTP-IN B4699D1493B74E85A8671850B09F08D3.MAI 1112 185.143.72.25 QUIT QUIT 221 Service closing transmission channel 42 6 [email protected]
06/23/20 22:34:02 SMTP-IN 3FE80CCEAA0942739F26259F1FB15696.MAI 1040 212.60.249.12 220 mail.example.com ESMTP MailEnable Service, Version: 7.59-7.59- ready at 06/23/20 22:34:02 0 0
06/23/20 22:34:02 SMTP-IN 9CBF0EE9385B47DE8E869EAFE6CC220D.MAI 1100 212.70.149.50 EHLO EHLO User 250-example.com [212.70.149.50], this server offers 5 extensions 143 11
06/23/20 22:34:03 SMTP-IN 3FE80CCEAA0942739F26259F1FB15696.MAI 1040 212.60.249.12 EHLO EHLO User 250-example.com [212.60.249.12], this server offers 5 extensions 143 11
06/23/20 22:34:04 SMTP-IN 9CBF0EE9385B47DE8E869EAFE6CC220D.MAI 1100 212.70.149.50 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:34:05 SMTP-IN 3FE80CCEAA0942739F26259F1FB15696.MAI 1040 212.60.249.12 RSET RSET 250 Requested mail action okay, completed 43 6
06/23/20 22:34:05 SMTP-IN 9CBF0EE9385B47DE8E869EAFE6CC220D.MAI 1100 212.70.149.50 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:34:06 SMTP-IN 3FE80CCEAA0942739F26259F1FB15696.MAI 1040 212.60.249.12 AUTH AUTH LOGIN 334 VXNlcm5hbWU6 18 12
06/23/20 22:34:07 SMTP-IN 9CBF0EE9385B47DE8E869EAFE6CC220D.MAI 1100 212.70.149.50 AUTH {blank} 334 UGFzc3dvcmQ6 18 22 [email protected]
06/23/20 22:34:08 SMTP-IN 3FE80CCEAA0942739F26259F1FB15696.MAI 1040 212.60.249.12 AUTH {blank} 334 UGFzc3dvcmQ6 18 30 [email protected]
06/23/20 22:34:08 SMTP-IN 9CBF0EE9385B47DE8E869EAFE6CC220D.MAI 1100 212.70.149.50 AUTH UEBzc3cwcmQ= 504 Invalid Username or Password 34 14 [email protected]
[06/23/20 22:34:09]****************** LOG FILE CLOSED ********************
我错过了什么？
更新 1
好的，我禁用了对入站端口 587 的要求 SSL，并在常规设置选项卡上选中了启用 TLS
然而，我缺少一个复选框Allow clients to establish secure sessions via STARTTLS，正如所见这里。
EnableSsl当我设置为时，邮件就会发送false。
现在。然而，当我尝试从[电子邮件保护]通过 smtp.example.com
Bad sequence of commands. The server response was: This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server.
我尝试使用相同的凭据[电子邮件保护]，但这些都不起作用。我应该在某处配置不同的凭据吗？
更新2
已升级并检查Allow clients to establish secure sessions via STARTTLS。然而，在最新的 MailEnable 版本中，[常规] 选项卡上不再有设置Enable TLS。我仍然收到错误：
命令序列错误。服务器响应为：此邮件服务器在尝试向非本地电子邮件地址发送邮件时需要身份验证。请检查您的邮件客户端设置或联系您的管理员以验证此服务器是否定义了域或地址。
我尝试过localhost不使用任何凭证发送（该电子邮件有效）和smtp.example.com使用凭证发送，但都失败了。我认为我需要通过发送，smtp.example.com因为我有该域的 SSL 证书，而当我通过发送时，localhost我需要我的 VPS 服务器域的 SSL 证书648gfhur343.stratserver.net，这是不可能的（因为通过 Let's Encrypt 颁发，问题不同）。
SMTP 日志
[06/27/20 14:17:27]****************** LOG FILE STARTED *******************
06/27/20 14:17:29 SMTP-IN A7DFBF7F65344DCD86F1FE13AC92DD20.MAI 844 212.60.249.12 220 mail.example.com ESMTP MailEnable Service, Version: 10.30-- ready at 06/27/20 14:17:29 94 0
06/27/20 14:17:30 SMTP-IN 21CF95A9113A47B581E1F0C4FDEB146A.MAI 840 85.214.200.31 220 mail.example.com ESMTP MailEnable Service, Version: 10.30-- ready at 06/27/20 14:17:30 94 0
06/27/20 14:17:30 SMTP-IN 21CF95A9113A47B581E1F0C4FDEB146A.MAI 840 85.214.200.31 EHLO EHLO h2746286 250-example.com [85.214.200.30], this server offers 5 extensions 237 15
06/27/20 14:17:30 SMTP-IN 21CF95A9113A47B581E1F0C4FDEB146A.MAI 840 85.214.200.31 MAIL MAIL FROM:<[email protected]> 250 Requested mail action okay, completed 43 34
06/27/20 14:17:30 SMTP-IN 21CF95A9113A47B581E1F0C4FDEB146A.MAI 840 85.214.200.31 RCPT RCPT TO:<[email protected]> 503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server. 235 33
[06/27/20 14:17:36]****************** LOG FILE CLOSED ********************
截图设置
答案1
EnableSsl 实际上不使用 SSL 连接到邮件服务器，而是不使用 SSL 进行连接并使用 STARTTLS 命令进行安全通信。您需要选中“启用 TLS”复选框，这样服务才能支持 STARTTLS 命令，但要关闭 587 端口配置的“需要 SSL”（或者在未使用 SSL 的情况下使用端口 25）。