diff --git a/roles/base/files/postfix/master.cf/master.cf.mailman b/roles/base/files/postfix/master.cf/master.cf.mailman
index e505fb55b1..3d5a2ddb1d 100644
--- a/roles/base/files/postfix/master.cf/master.cf.mailman
+++ b/roles/base/files/postfix/master.cf/master.cf.mailman
@@ -6,7 +6,12 @@
 # service type  private unpriv  chroot  wakeup  maxproc command + args
 #               (yes)   (yes)   (yes)   (never) (100)
 # ==========================================================================
+
+# Mail received from outside: spam checking is enabled.
 smtp      inet  n       -       n       -       -       smtpd -o content_filter=spamassassin
+# Mail received from Mailman: only localhost on the submission port, no spam checking.
+localhost:submission inet n       -       n       -       -       smtpd
+
 #submission inet n       -       n       -       -       smtpd
 #  -o smtpd_enforce_tls=yes
 #  -o smtpd_sasl_auth_enable=yes
diff --git a/roles/mailman/templates/mailman.cfg.j2 b/roles/mailman/templates/mailman.cfg.j2
index cce9b0d3dc..cea350a45c 100644
--- a/roles/mailman/templates/mailman.cfg.j2
+++ b/roles/mailman/templates/mailman.cfg.j2
@@ -68,6 +68,11 @@ header_checks:
 jump_chain: discard
 
 
+[mta]
+# Email is sent on the submission port to bypass spam checking.
+smtp_port: 587
+
+
 [language.en]
 # Change the english language to be UTF-8 (it defaults to ascii).
 description: English (USA)