Explain why network port configurations are so vital in preventing an intrusion and safeguarding data

Explain why network port configurations are so vital in preventing an intrusion and safeguarding data. Discuss key ports that are typically used in most network environments (think HTTP/HTTPS/FTP/etc., among others).   
Explain the difference between an Intrusion Detection System (IDS) and Intrusion Prevention system (IPS)? Specifically capture and discuss where and how Cyber Threat Hunting fits into IDS and IPS systems.
Explain how the use of Virtual Local Area Networks (VLANS) could prevent the lateral spread of malware in an organizations network. Provide empirical examples of how you would use a VLAN configuration to segment separate systems and detail why certain systems would be able to communicate with others.