diff --git a/pillar.example b/pillar.example
index ff6628dcd973abd902af548111dbd9d1f6a0cf1a..dbe06567071b3df45d3707c4cf7f5ef91ac70750 100644
--- a/pillar.example
+++ b/pillar.example
@@ -1,4 +1,5 @@
 postfix:
   nullclient:
+    message_size_limit: '10240000'
     relayhost: 'smtp.example.com'
     rootmail-destination: 'rootmails@example.com'
diff --git a/postfix/nullclient/etc/postfix/main.cf b/postfix/nullclient/etc/postfix/main.cf
index 84cbb1e326708ce3c8fdf58abe3c71736c5662b8..79d1f7e1166dba3c06dc31bdbe3038aa8ce30f41 100644
--- a/postfix/nullclient/etc/postfix/main.cf
+++ b/postfix/nullclient/etc/postfix/main.cf
@@ -54,3 +54,5 @@ enable_long_queue_ids = yes
 # Disable smtputf8 support since exchange does not support it
 smtputf8_enable = no
 
+# Allow configuring maximum message size
+message_size_limit = {{ pillar['message_size_limit'] }}