diff --git a/roles/mail_forwarder/molecule/default/tests/test_mandatory.py b/roles/mail_forwarder/molecule/default/tests/test_mandatory.py
index 622504e2b7fafbfb388ebefd7861da3f09241d50..77987ffa153ca7271cb361eb612a59ed71c5e39f 100644
--- a/roles/mail_forwarder/molecule/default/tests/test_mandatory.py
+++ b/roles/mail_forwarder/molecule/default/tests/test_mandatory.py
@@ -68,3 +68,17 @@ def test_direct_mail_sending(host):
         pattern = r"%s: to=<root@domain1>, relay=domain1\[[^]]*\]:25.*status=sent" % message_id
 
         assert re.search(pattern, mail_log.content_string) is not None
+
+
+def test_mail_message_size_limit(host):
+    """
+    Tests if the mail message size limit advertised by the SMTP server
+    is correct.
+    """
+
+    capabilities = host.run("(echo 'ehlo localhost' && sleep 2) | telnet localhost 25")
+    begin = capabilities.stdout.find("250-SIZE")
+    end = capabilities.stdout.find("\n", begin)
+    mail_message_size_limit = capabilities.stdout[begin:end]
+
+    assert mail_message_size_limit == "250-SIZE 10240000"