Understanding DMZ Architecture in Servicenow Discovery

[Charu Maurya]

I have a basic understanding of discovery; however, I want to better understand how DMZ works in real enterprise environments.

I have some questions and would appreciate guidance from experienced professionals:

1. What exactly is a DMZ in networking terms?
2. Why do organizations place servers in a DMZ instead of the internal network?
3. In ServiceNow Discovery, why is a MID Server sometimes installed inside the DMZ?
4. How does communication happen between:
   • ServiceNow instance
   • MID Server
   • DMZ servers/devices
5. What firewall ports are usually opened for Discovery in a DMZ setup?
6. Is inbound connectivity from ServiceNow to the MID Server required?
7. When should we use the following:
   • one MID Server
   • multiple MID Servers
   • separate MID Servers for the internal network and the DMZ
8. Can someone share a simple real-world architecture example or best practice for Discovery in a DMZ environment?
9. What are common mistakes or security concerns while configuring Discovery for DMZ systems?

I would also appreciate any documentation, diagrams, or learning resources