Table of Contents

About

This article will show different server configuration testing in order to validate your email server configuration.

In our case, we had installed Postfix

Technics

Sending an email to Provider

Testing an email configuration is done by sending an email to a provider that will:

  • show you if you pass the tests
  • eventually score your email.

Mail Tester

The most easy way is to send an email at mail-tester

Opendkim Test Mailer

Gmail

Send an email and check the original email, Gmail will show you if you have passed the test:

Gmail Original Message Dkim Test

Testing locally with netcat

Network - netcat (nc, ncat)

nc mail.example.com 25
EHLO $hostname
250-server01.bytle.net
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN

MAIL FROM:<[email protected]>
RCPT TO:<[email protected]>
DATA
Subject: Test email

Body of the email
.
QUIT