diff --git a/roles/mail_server/molecule/default/tests/test_default.py b/roles/mail_server/molecule/default/tests/test_default.py
index c7774ed477724fe5f8f291a5d4a869539ebc9488..f3a2e71b5faedc4bcfdf22bd6a9f710aaa08f8e9 100644
--- a/roles/mail_server/molecule/default/tests/test_default.py
+++ b/roles/mail_server/molecule/default/tests/test_default.py
@@ -355,3 +355,44 @@ def test_firewall_configuration_file(host):
         assert config.user == 'root'
         assert config.group == 'root'
         assert config.mode == 0o640
+
+
+def test_smtp_server_dh_parameter_file(host):
+    """
+    Tests if the Diffie-Helman parameter file has been generated
+    correctly.
+    """
+
+    hostname = host.run('hostname').stdout.strip()
+    dhparam_file_path = '/etc/ssl/private/%s_smtp.dh.pem' % hostname
+
+    with host.sudo():
+        dhparam_file = host.file(dhparam_file_path)
+        assert dhparam_file.is_file
+        assert dhparam_file.user == 'root'
+        assert dhparam_file.group == 'root'
+        assert dhparam_file.mode == 0o640
+
+        dhparam_info = host.run("openssl dhparam -noout -text -in %s", dhparam_file_path)
+
+        assert "DH Parameters: (2048 bit)" in dhparam_info.stdout
+
+
+def test_smtp_server_uses_correct_dh_parameters(host):
+    """
+    Tests if the SMTP server uses the generated Diffie-Helman parameter.
+    """
+
+    hostname = host.run('hostname').stdout.strip()
+
+    with host.sudo():
+        expected_dhparam = host.file('/etc/ssl/private/%s_smtp.dh.pem' % hostname).content_string.rstrip()
+
+    connection = host.run("gnutls-cli --no-ca-verification --starttls-proto=smtp --port 25 --priority 'NONE:+VERS-TLS1.2:+CTYPE-X509:+COMP-NULL:+SIGN-RSA-SHA384:+DHE-RSA:+SHA384:+AEAD:+AES-256-GCM' --verbose localhost")
+
+    output = connection.stdout
+    begin_marker = "-----BEGIN DH PARAMETERS-----"
+    end_marker = "-----END DH PARAMETERS-----"
+    used_dhparam = output[output.find(begin_marker):output.find(end_marker) + len(end_marker)]
+
+    assert used_dhparam == expected_dhparam