diff --git a/postfix/defaults/main.yml b/postfix/defaults/main.yml
index 83d7015e462dce89251c2ac3a2f56ff0d5647071..7d3cd45a29beb50b945ef5b94502b7bed351bcc1 100644
--- a/postfix/defaults/main.yml
+++ b/postfix/defaults/main.yml
@@ -28,6 +28,7 @@ postfix_network_access:
   - cidr: 134.130.5.32/27  # rwth
     action: permit
 postfix_content_filter: false  # or: spamassassin
+postfix_message_size_limit: 10240000  # 10M
 
 postfix_aliases_rt: []
 #  - queue: IT
diff --git a/postfix/templates/main.cf.j2 b/postfix/templates/main.cf.j2
index 1138a635a645a24a1a40af8685b8e41bf769f27f..6afd5c31c2d7b31427a1ba24c39a6bf45479298c 100644
--- a/postfix/templates/main.cf.j2
+++ b/postfix/templates/main.cf.j2
@@ -35,7 +35,7 @@ compatibility_level = 2
 disable_vrfy_command = yes
 #enable_long_queue_ids = yes
 mailbox_size_limit = 0
-#message_size_limit = 41943040
+message_size_limit = {{ postfix_message_size_limit }}
 readme_directory = no
 recipient_delimiter = +
 #strict_rfc821_envelopes = no