diff --git a/mail/postfix/Makefile b/mail/postfix/Makefile
index 659bcd8c19..f0c2159c3b 100644
--- a/mail/postfix/Makefile
+++ b/mail/postfix/Makefile
@@ -1,6 +1,6 @@
 PLUGIN_NAME=		postfix
 PLUGIN_VERSION=		1.23
-PLUGIN_REVISION=	3
+PLUGIN_REVISION=	4
 PLUGIN_COMMENT=		SMTP mail relay
 PLUGIN_DEPENDS=		postfix
 PLUGIN_MAINTAINER=	m.muenz@gmail.com
diff --git a/mail/postfix/src/opnsense/service/templates/OPNsense/Postfix/main.cf b/mail/postfix/src/opnsense/service/templates/OPNsense/Postfix/main.cf
index 5ce384efad..3857806567 100644
--- a/mail/postfix/src/opnsense/service/templates/OPNsense/Postfix/main.cf
+++ b/mail/postfix/src/opnsense/service/templates/OPNsense/Postfix/main.cf
@@ -80,6 +80,7 @@ smtpd_banner = $myhostname ESMTP Postfix
 {% endif %}
 {% if helpers.exists('OPNsense.postfix.general.message_size_limit') and OPNsense.postfix.general.message_size_limit != '' %}
 message_size_limit = {{ OPNsense.postfix.general.message_size_limit }}
+mailbox_size_limit = {{ OPNsense.postfix.general.message_size_limit }}
 {% endif %}
 {% if helpers.exists('OPNsense.postfix.general.masquerade_domains') and OPNsense.postfix.general.masquerade_domains != '' %}
 masquerade_domains = {{ OPNsense.postfix.general.masquerade_domains }}