diff --git a/deploy-chatmail/src/deploy_chatmail/postfix/main.cf.j2 b/deploy-chatmail/src/deploy_chatmail/postfix/main.cf.j2
index 303aed13..975a5241 100644
--- a/deploy-chatmail/src/deploy_chatmail/postfix/main.cf.j2
+++ b/deploy-chatmail/src/deploy_chatmail/postfix/main.cf.j2
@@ -29,6 +29,9 @@ myhostname = {{ config.domain_name }}
 alias_maps = hash:/etc/aliases
 alias_database = hash:/etc/aliases
 
+# hard limit, also on internal messages
+smtpd_client_message_rate_limit = 80
+
 # Postfix does not deliver mail for any domain by itself.
 # Primary domain is listed in `virtual_mailbox_domains` instead
 # and handed over to Dovecot.