So überprüfen Sie, ob SMTP von der Befehlszeile aus funktioniert (Linux)

Die einzige Sache bei der Verwendung von Telnet zum Testen von Postfix oder anderem SMTP ist, dass Sie die Befehle und die Syntax kennen müssen. Verwenden Sie stattdessen einfach Swaks :)

example@unixlinux.online:~$ 
example@unixlinux.online:~$ mail -f Maildir
"/home/thufir/Maildir": 4 messages
>    1 example@unixlinux.online                   15/553   test Mon, 30 Dec 2013 10:15:12 -0800
     2 example@unixlinux.online                   15/581   test Mon, 30 Dec 2013 10:15:55 -0800
     3 example@unixlinux.online                   15/581   test Mon, 30 Dec 2013 10:29:57 -0800
     4 example@unixlinux.online                   15/581   test Mon, 30 Dec 2013 11:54:16 -0800
? q
Held 4 messages in /home/thufir/Maildir
example@unixlinux.online:~$ 
example@unixlinux.online:~$ swaks --to example@unixlinux.online
=== 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:<example@unixlinux.online>
<-  250 2.1.0 Ok
 -> RCPT TO:<example@unixlinux.online>
<-  250 2.1.5 Ok
 -> DATA
<-  354 End data with <CR><LF>.<CR><LF>
 -> Date: Mon, 30 Dec 2013 14:33:17 -0800
 -> To: example@unixlinux.online
 -> From: example@unixlinux.online
 -> 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.
example@unixlinux.online:~$ 
example@unixlinux.online:~$ mail -f Maildir
"/home/thufir/Maildir": 5 messages 1 new
     1 example@unixlinux.online                   15/553   test Mon, 30 Dec 2013 10:15:12 -0800
     2 example@unixlinux.online                   15/581   test Mon, 30 Dec 2013 10:15:55 -0800
     3 example@unixlinux.online                   15/581   test Mon, 30 Dec 2013 10:29:57 -0800
     4 example@unixlinux.online                   15/581   test Mon, 30 Dec 2013 11:54:16 -0800
>N   5 example@unixlinux.online                   15/581   test Mon, 30 Dec 2013 14:33:17 -0800
? 5
Return-Path: <example@unixlinux.online>
X-Original-To: example@unixlinux.online
Delivered-To: example@unixlinux.online
Received: from dur.bounceme.net (localhost [127.0.0.1])
    by dur.bounceme.net (Postfix) with ESMTP id 52D162C3EFF
    for <example@unixlinux.online>; Mon, 30 Dec 2013 14:33:17 -0800 (PST)
Date: Mon, 30 Dec 2013 14:33:17 -0800
To: example@unixlinux.online
From: example@unixlinux.online
Subject: test Mon, 30 Dec 2013 14:33:17 -0800
X-Mailer: swaks v20130209.0 jetmore.org/john/code/swaks/
Message-Id: <example@unixlinux.online>

This is a test mailing

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

Es ist nur ein einfacher Befehl.

[example@unixlinux.online tmp]# mail -v example@unixlinux.online
Subject: Test
Hello world
Cc:  <Ctrl+D>

example@unixlinux.online Connecting to [127.0.0.1] via relay...
220 piwik-dev.example.com ESMTP Sendmail 8.13.8/8.13.8; Thu, 23 Aug 2012 10:49:40 -0400
>>> EHLO piwik-dev.example.com
250-piwik-dev.example.com Hello localhost.localdomain [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-DELIVERBY
250 HELP
>>> MAIL From:<example@unixlinux.online> SIZE=46
250 2.1.0 <example@unixlinux.online>... Sender ok
>>> RCPT To:<example@unixlinux.online>
>>> DATA
250 2.1.5 <example@unixlinux.online>... Recipient ok
354 Enter mail, end with "." on a line by itself
>>> .
250 2.0.0 q7NEneju002633 Message accepted for delivery
example@unixlinux.online Sent (q7NEneju002633 Message accepted for delivery)
Closing connection to [127.0.0.1]
>>> QUIT
221 2.0.0 piwik-dev.example.com closing connection

Die Syntax zum Herstellen einer unformatierten Netzwerkverbindung mit Telnet lautet wie folgt:

telnet {domain_name} {port_number}

Also telnet zu deinem SMTP-Server wie

telnet smtp.mydomain.example 25

Kopieren Sie das Folgende und fügen Sie es ein

helo client.mydomain.example
mail from:<example@unixlinux.online>
rcpt to:<example@unixlinux.online>
data
From: example@unixlinux.online
Subject: test mail from command line

this is test number 1
sent from linux box
.
quit

Hinweis: Vergessen Sie nicht das "." am Ende, das das Ende der Nachricht darstellt. Die Zeile "quit" beendet die Sitzung.