diff --git a/roles/mail_forwarder/tests/test_mandatory.py b/roles/mail_forwarder/tests/test_mandatory.py
index 271ef0f9b7aaa5f0e3c69802fc4178446508afc9..b30b10833ff91cf509e7cda9a98a13387787483a 100644
--- a/roles/mail_forwarder/tests/test_mandatory.py
+++ b/roles/mail_forwarder/tests/test_mandatory.py
@@ -61,6 +61,7 @@ def test_direct_mail_sending(Command, File, Sudo):
 
     with Sudo():
         mail_log = File('/var/log/mail.log')
-        pattern = "%s: to=<root@domain1>, relay=domain1.*status=sent" % message_id
+        # Pattern used to verify the mail was sent directly on default port.
+        pattern = "%s: to=<root@domain1>, relay=domain1\[[^]]*\]:25.*status=sent" % message_id
 
         assert re.search(pattern, mail_log.content) is not None