diff --git a/target/start-mailserver.sh b/target/start-mailserver.sh
index 9c43d43a..0c823d51 100644
--- a/target/start-mailserver.sh
+++ b/target/start-mailserver.sh
@@ -776,6 +776,13 @@ function _setup_ssl() {
 			sed -i -e 's~ssl_cert = </etc/dovecot/dovecot\.pem~ssl_cert = </etc/postfix/ssl/cert~g' /etc/dovecot/conf.d/10-ssl.conf
 			sed -i -e 's~ssl_key = </etc/dovecot/private/dovecot\.pem~ssl_key = </etc/postfix/ssl/key~g' /etc/dovecot/conf.d/10-ssl.conf
 
+			if [ -n "$SSL_BUNDLE_PATH" ]; then
+				cp "$SSL_BUNDLE_PATH" /etc/postfix/ssl/bundle
+				chmod 600 /etc/postfix/ssl/bundle
+
+				sed -i -r 's~#smtpd_tls_CAfile=~smtpd_tls_CAfile=/etc/postfix/ssl/bundle~g' /etc/postfix/main.cf
+			fi
+
 			notify 'inf' "SSL configured with 'Manual' certificates"
 		fi
 	;;