1. What are the three main elements that make up a DiD strategy?
   1. People, technology, and operating methods
   2. Firewall, antivirus, and people
   3. Patching, physical barrier, and people
2. Which is the main feature that differentiates a stateful firewall?
   1. Packet filtering
   2. TCP session modelling
   3. Packet inspection at the application layer

3. What is the main advantage of a DMZ?
   1. Segregation of the control network
   2. Being able to create and deploy devices that act as dual-homes in a specific network 
   3. Monitoring traffic crossing networks

4. What is the main advantage of a VLAN?
   1. Segregating the control network
   2. Building up a DMZ
   3. Building logical networks that share the same physical infrastructure

5. What is the main security constraint of the edge in an OPC DCOM deployment setup?
   1. Allowing DCOM traffic to cross the firewall
   2. Using a DPI firewall for filtering OPC packets
   3. Building up a DMZ to segregate the OPC Classic server

6. What is the main advantage of the edge in on OPC Proxy deployment setup?
   1. Tunneling the DCOM traffic through TCP 
   2. Tunneling the DCOM traffic through TCP and putting the external OPC Proxy in a DMZ
   3. Segregating OPC Classic, since all requests pass through the internal OPC Proxy

7. What is the main feature from a security perspective of the edge in an OPC-UA deployment setup?
   1. Using a DPI firewall
   2. Using the OPC-UA security model