diff --git a/install/debian/10/exim/exim4.conf.template b/install/debian/10/exim/exim4.conf.template
index cb6c960c3..7cc13c364 100644
--- a/install/debian/10/exim/exim4.conf.template
+++ b/install/debian/10/exim/exim4.conf.template
@@ -25,6 +25,9 @@ acl_smtp_rcpt = acl_check_rcpt
 acl_smtp_data = acl_check_data
 acl_smtp_mime = acl_check_mime
 
+recipients_max = 15
+recipients_max_reject = true
+
 # log_selector = +smtp_connection
 smtp_accept_max = 50
 smtp_accept_max_per_host = 4