A firewall is highly recommended if your Advantech WebAccess/SCADA Project and SCADA nodes are exposed to the Internet (i.e. you are using Public IP Addresses). This will increase the security of your system. A firewall appliance is recommended. For more information, see 1.6.1 Firewalls.
Figure 1.2.2.1 - Firewall with access to SCADA Nodes using Public IP Address