Mail Services Testing

Sending a Test Message

$ echo "Hello World" | mail -s "Test Message" john@example.net

Test Mail Routing

Produce two types of mail delivery reports for debugging:

What-If

Rport what would happen, but do not actually deliver mail. This mode of operation is requested with:

$ /usr/sbin/sendmail -bv user@domain.tld

SMTP Sessions

Note

Note the space in front of the command-line. It avoids saving your password in the command-line history.

Preparing username and password for the AUTH-PLAIN method:

$  echo -ne '\000john@example.net\000********' | base64 -w0 ; echo
AGpvaG5AZXhhbXBsZS5uZXQAKioqKioqKio=

Preparing username and password for the LOGIN method:

$ echo -ne 'john@example.net' | base64 -w0 ; echo
am9obkBleGFtcGxlLm5ldA==
$  echo -ne '********' | base64 -w0 ; echo
KioqKioqKio=

Submission Server

$ openssl s_client -starttls smtp -connect mail.example.net:submission

> 220 mail.example.net ESMTP Postfix
EHLO torres.example.net
> 250-mail.urown.net
> 250-PIPELINING
> 250-SIZE 26214400
> 250-VRFY
> 250-ETRN
> 250-AUTH PLAIN LOGIN
> 250-AUTH=PLAIN LOGIN
> 250-ENHANCEDSTATUSCODES
> 250-8BITMIME
> 250-DSN
> 250-SMTPUTF8
> 250 CHUNKING

AUTH PLAIN

AUTH PLAIN AGpvaG5AZXhhbXBsZS5uZXQAKioqKioqKio=
> 235 2.7.0 Authentication successful

AUTH LOGIN

AUTH LOGIN
334
am9obkBleGFtcGxlLm5ldA==
334
KioqKioqKio=

SMTP Secure Server

$ openssl s_client -connect mail.example.net:ssmtp

Mail Message

EHLO torres.example.net
AUTH PLAIN AGpvaG5AZXhhbXBsZS5uZXQAKioqKioqKio=
> 235 2.7.0 Authentication successful
MAIL FROM:<john@torres.example.net>
> 250 2.1.0 Ok
rcpt to:<john@example.net>
> 250 2.1.5 Ok
DATA
> 354 End data with <CR><LF>.<CR><LF>
Message-ID: <8b16a38d-20dd-25eb-fa2b-8603e8e9f68c@example.net>
Date: Sun, 3 Jul 2022 20:58:50 +0200
MIME-Version: 1.0
Subject: Test Message
To: John Doe <john@example.net>
Content-Language: en-US
From: John Doe <john@torres.example.net>
Subject: Test Message

Hi,

This is a test message.

Best,
Widmore
.
> 250 2.0.0 Ok: queued as CDD461A811EA
QUIT
> DONE

Postfix Logs

$ journalctrl -t

postfix postfix/dnsblog postfix/master postfix/postmap postfix/sendmail postfix/tlsproxy postfix/anvil postfix/error postfix/pickup postfix/postscreen postfix/smtp postfix/trivial-rewrite postfix/bounce postfix/lmtp postfix/postalias postfix/qmgr postfix/smtpd postfix/verify postfix/cleanup postfix/local postfix/postfix-script postfix/scache postfix/submission/smtpd postfix/virtual