Recipe 20.4. Testing the SMTP/POP3 Mail Server
20.4.1 Problem
You want
to verify that the various server components are working.
20.4.2 Solution
Our old friend telnet and our new friend
openssl s_client will do the job.
Test the
SMTP server with telnet:
$ telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain.
Escape character is '^]'.
220 windbag.test.net ESMTP Postfix (Libranet/GNU)
ehlo windbag
250-windbag.test.net
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-XVERP
250 8BITMIME
mail from: foober@test.net
250 Ok
rcpt to: carla@test.net
250 Ok
data
354 End data with <CR><LF>.<CR><LF>
Date: Jan 15, 2004
From: foober
Reply-to: foober@test.net
Message-ID: six
Subject: telnet test
Hi Carla,
Did you get this?
.
250 Ok: queued as 6069F2290C
quit
221 Bye
Connection closed by foreign host.
Also test plain, unencrypted
POP3 with telnet:
$ telnet localhost 110
Trying 127.0.0.1...
Connected to localhost.localdomain.
Escape character is '^]'.
+OK Hello there.
user carla
+OK Password required.
pass sekritword
+OK logged in.
stat
+OK 2 1275
list
+OK POP3 clients that break here, they violate STD53.
1 638
2 637
.
retr 1
+OK 638 octets follow.
Return-Path: <stinkpad@test.net>
X-Original-To: carla@test.net
Delivered-To: carla@test.net
Received: from 192.168.1.100 (unknown [192.168.1.100])
by windbag.test.net (Postfix) with ESMTP id 409E722884
for <carla@test.net>; Thu, 15 Jan 2004 15:29:54 -0700 (PDT)
From: stinkpad <stinkpad@test.net>
To: carla@test.net
Subject: telnet test
Date: Thu, 15 Jan 2004 15:29:50 -0700
User-Agent: KMail/1.5.4
MIME-Version: 1.0
Content-Type: text/plain;
charset="us-ascii"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200401151529.50714.stinkpad@test.net>
Hi Carla,
Did you get this?
.
quit
+OK Bye-bye.
Connection closed by foreign host.
Test TLS/SSL support with openssl s_client.
Use the POP3 mail commands:
$ openssl s_client -connect localhost:995
CONNECTED(00000003)
depth=0 /C=US/ST=NM/L=Albuquerque/O=Courier Mail Server/OU=Automatically-generated POP3 SSL
key/CN=windbag/emailAddress=postmaster@test.net
verify error:num=18:self signed certificate
...
<many lines of certificate data and protocols>
---
+OK Hello there.
user carla
+OK Password required.
pass sekritword
+OK logged in.
Continue just as you would with any POP3 session.
You can test client connectivity by hostname or IP:
$ telnet windbag 25
$ telnet 192.168.1.5 110
$ openssl s_client -connect windbag:995
20.4.3 Discussion
Here are some of the more common POP3 commands:
- list
-
Show a list of messages, by number, with the number of bytes in each
message.
- top msg lines
-
Display the message header of message msg and
display lines many lines. For example,
top 3 5 displays the headers of message 3 and
the first 5 lines of the body of the message.
- retr msg
-
Display the message, selected by number (e.g., retr
2).
- dele n
-
Delete message number n.
- rset
-
Undelete any messages that are marked for deletion.
- quit
-
Delete messages marked for deletion, and log out.
20.4.4 See Also
RFC 1939 for a complete description of POP commands This chapter's
"Introduction," for a list of ports
for the different mail protocols telnet(1)
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