diff --git a/roles/mail_server/molecule/default/tests/test_optional.py b/roles/mail_server/molecule/default/tests/test_optional.py
index c8079027080cd50e5b6c11e5f44a1836093679b8..f5d26e81446d139876be7bfd73c488811c561164 100644
--- a/roles/mail_server/molecule/default/tests/test_optional.py
+++ b/roles/mail_server/molecule/default/tests/test_optional.py
@@ -301,3 +301,17 @@ def test_sieve_tls_configuration(host):
     # @TODO: Currently not possible to test since openssl s_client does not
     # support STARTTLS for Sieve.
     pass
+
+
+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 20480001"