In some restrictive environments, only certain outgoing communication is allowed. To make sure that the Multy X can successfully communicate with the cloud, the following ports/protocols should be allowed outgoing for the Multy X:
443 (HTTPS) sending/receiving config/monitor information
53 (DNS) name resolution to reach the myZyxelCloud
1 (ICMP) connectivity check to myZyxelCloud
Please note that no NAT is needed on the router located in front of the Multy X system.