How to check if smtp is working from commandline (Linux)

Question

I have a SMTP-server, for the purpose of this question lets call it: smtp.mydomain.com.

How do i check if the SMTP-server is in working? Can I send emails manually from Linux commandline?

Solution 1

Syntax for establishing a raw network connection using telnet is this:

telnet {domain_name} {port_number}

So telnet to your smtp server like

telnet smtp.mydomain.com 25

And copy and paste the below

helo client.mydomain.com
mail from:<[email protected]>
rcpt to:<[email protected]>
data
From: [email protected]
Subject: test mail from command line

this is test number 1
sent from linux box
.
quit

Note : Do not forgot the "." at the end which represents the end of the message. The "quit" line exits ends the session.

Solution 2

The only thing about using telnet to test postfix, or other SMTP, is that you have to know the commands and syntax. Instead, just use swaks :)

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

This is a test mailing

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

It's just one easy command.

Solution 3

[root@piwik-dev tmp]# mail -v root@localhost
Subject: Test
Hello world
Cc:  <Ctrl+D>

root@localhost... 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:<[email protected]> SIZE=46
250 2.1.0 <[email protected]>... Sender ok
>>> RCPT To:<[email protected]>
>>> DATA
250 2.1.5 <[email protected]>... Recipient ok
354 Enter mail, end with "." on a line by itself
>>> .
250 2.0.0 q7NEneju002633 Message accepted for delivery
root@localhost... Sent (q7NEneju002633 Message accepted for delivery)
Closing connection to [127.0.0.1]
>>> QUIT
221 2.0.0 piwik-dev.example.com closing connection

Solution 4

Not sure if this help or not but this is a command line tool which let you simply send test mails from a SMTP server priodically. http://code.google.com/p/woodpecker-tester/

View more solutions

Comments

[tripleee]

You should wait for the servers's response to each command, and abort if you get and error (4xx or 5xx result code).

[martineg]

You need a blank line between headers and message, apart fram that it's a working example.

[balanv]

@tripleee : actually when i pasted this in telnet, i can get email from smtp server. Note : Afte the "." at end, i left a line break.

[tripleee]

Good for you. In the general case, you are behaving like a spammer, which will make some servers hang up on you.

[jgrocha]

Instead of hello velanapps.com you should write helo velanapps.com and if you want to know which smtp extensions are available, you should write ehlo velanapps.com, as in SMTP Example

[Peter Loron]

I didn't know about swaks. Thanks!

[rhand]

you can exit by typing quit

[Jeremy]

This answer was useful, however I omitted the first line in my tests. I stil got emails through from the smtp server. It would be helpful if you could include a little bit about what the velanapps.com domain is doing here. I am always wary when I see a domain used for something like this with no explanation as to what its doing with our data. Thanks.

[balanv]

@Jeremy Its just a sample data, i have removed it and added placeholder...

[Bruno Bronosky]

"I found this on the web, and added this to Stack Overflow as many end up here." Bless your heart.

[vladkras]

this works only if I switch to line mode with ^] and l consecutively

[Erdal G.]

Just tried swaks is great, wow! And available as a standart package in Debian