如何从命令行检查 SMTP 是否工作（Linux）

Question

我有一个 SMTP 服务器，出于这个问题的目的，我们称之为： smtp.mydomain.example 。

如何检查 SMTP 服务器是否在工作？我可以从 Linux 命令行手动发送电子邮件吗？

原文由 balanv 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

使用 telnet 建立原始网络连接的语法如下：

 telnet {domain_name} {port_number}

所以 telnet 到你的 SMTP 服务器，比如

telnet smtp.mydomain.example 25

并复制并粘贴以下内容

helo client.mydomain.example
mail from:<[e-mail]>
rcpt to:<[e-mail]>
data
From: [e-mail]
Subject: test mail from command line

this is test number 1
sent from linux box
.
quit

注意： 不要忘记“。”最后代表消息的结束。 “退出”行退出结束会话。

原文由 balanv 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

使用 telnet 测试 postfix 或其他 SMTP 的唯一事情是您必须了解命令和语法。相反，只需使用 swaks :)

 thufir@dur:~$
thufir@dur:~$ mail -f Maildir
"/home/thufir/Maildir": 4 messages
>    1 [e-mail]                   15/553   test Mon, 30 Dec 2013 10:15:12 -0800
     2 [e-mail]                   15/581   test Mon, 30 Dec 2013 10:15:55 -0800
     3 [e-mail]                   15/581   test Mon, 30 Dec 2013 10:29:57 -0800
     4 [e-mail]                   15/581   test Mon, 30 Dec 2013 11:54:16 -0800
? q
Held 4 messages in /home/thufir/Maildir
thufir@dur:~$
thufir@dur:~$ swaks --to [e-mail]
=== Trying dur.bounceme.net:25...
=== Connected to dur.bounceme.net.
<-  220 dur.bounceme.net ESMTP Postfix (Ubuntu)
 -> EHLO dur.bounceme.net
<-  250-dur.bounceme.net
<-  250-PIPELINING
<-  250-SIZE 10240000
<-  250-VRFY
<-  250-ETRN
<-  250-STARTTLS
<-  250-ENHANCEDSTATUSCODES
<-  250-8BITMIME
<-  250 DSN
 -> MAIL FROM:<[e-mail]>
<-  250 2.1.0 Ok
 -> RCPT TO:<[e-mail]>
<-  250 2.1.5 Ok
 -> DATA
<-  354 End data with <CR><LF>.<CR><LF>
 -> Date: Mon, 30 Dec 2013 14:33:17 -0800
 -> To: [e-mail]
 -> From: [e-mail]
 -> Subject: test Mon, 30 Dec 2013 14:33:17 -0800
 -> X-Mailer: swaks v20130209.0 jetmore.org/john/code/swaks/
 ->
 -> This is a test mailing
 ->
 -> .
<-  250 2.0.0 Ok: queued as 52D162C3EFF
 -> QUIT
<-  221 2.0.0 Bye
=== Connection closed with remote host.
thufir@dur:~$
thufir@dur:~$ mail -f Maildir
"/home/thufir/Maildir": 5 messages 1 new
     1 [e-mail]                   15/553   test Mon, 30 Dec 2013 10:15:12 -0800
     2 [e-mail]                   15/581   test Mon, 30 Dec 2013 10:15:55 -0800
     3 [e-mail]                   15/581   test Mon, 30 Dec 2013 10:29:57 -0800
     4 [e-mail]                   15/581   test Mon, 30 Dec 2013 11:54:16 -0800
>N   5 [e-mail]                   15/581   test Mon, 30 Dec 2013 14:33:17 -0800
? 5
Return-Path: <[e-mail]>
X-Original-To: [e-mail]
Delivered-To: [e-mail]
Received: from dur.bounceme.net (localhost [127.0.0.1])
    by dur.bounceme.net (Postfix) with ESMTP id 52D162C3EFF
    for <[e-mail]>; Mon, 30 Dec 2013 14:33:17 -0800 (PST)
Date: Mon, 30 Dec 2013 14:33:17 -0800
To: [e-mail]
From: [e-mail]
Subject: test Mon, 30 Dec 2013 14:33:17 -0800
X-Mailer: swaks v20130209.0 jetmore.org/john/code/swaks/
Message-Id: <[e-mail]>

This is a test mailing

New mail has arrived.
? q
Held 5 messages in /home/thufir/Maildir
thufir@dur:~$

这只是一个简单的命令。

原文由 Thufir 发布，翻译遵循 CC BY-SA 3.0 许可协议