diff --git a/baseimage/initializeBaseUbuntuImage.sh b/baseimage/initializeBaseUbuntuImage.sh
index 09d74ab6a..e9a3311b0 100644
--- a/baseimage/initializeBaseUbuntuImage.sh
+++ b/baseimage/initializeBaseUbuntuImage.sh
@@ -67,9 +67,9 @@ iptables -P OUTPUT ACCEPT
 # allow ssh, http, https, ping, dns
 iptables -I INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
 if [ ${SELFHOSTED} == 0 ]; then
-    iptables -A INPUT -p tcp -m tcp -m multiport --dports 25,80,202,443,587,993 -j ACCEPT
+    iptables -A INPUT -p tcp -m tcp -m multiport --dports 25,80,202,443,587,993,4190 -j ACCEPT
 else
-    iptables -A INPUT -p tcp -m tcp -m multiport --dports 25,80,22,443,587,993 -j ACCEPT
+    iptables -A INPUT -p tcp -m tcp -m multiport --dports 25,80,22,443,587,993,4190 -j ACCEPT
 fi
 iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
 iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT
diff --git a/src/apps.js b/src/apps.js
index 14cb218b5..12b2a8503 100644
--- a/src/apps.js
+++ b/src/apps.js
@@ -141,6 +141,7 @@ function validatePortBindings(portBindings, tcpPorts) {
         config.get('oauthProxyPort'), /* oauth proxy server (lo) */
         config.get('simpleAuthPort'), /* simple auth server (lo) */
         3306, /* mysql (lo) */
+        4190, /* managesieve */
         8000 /* graphite (lo) */
     ];