In this scenario, the best technology to ensure that internal servers are not directly accessible from the internet while allowing them to initiate connections to external services is a Proxy Server. A Proxy Server acts as an intermediary, forwarding requests from internal clients to external services while masking the internal server's identity. It provides security and control over outgoing connections. Firewalls and VPNs are primarily used for different purposes, and NAT doesn't provide the necessary level of control.

Port Numbers are numerical labels assigned to specific processes running on a host to differentiate them. These ports are used to direct network traffic to the appropriate applications or services running on a device.

Lucy is reading about the TCP/IP model, which consists of four layers: Network Interface (Link), Internet (Network), Transport, and Application. This model is fundamental to modern networking and is used as a reference framework for network protocols.

HTTPS (Hypertext Transfer Protocol Secure) provides a secure version of HTTP by using encryption, typically SSL/TLS. This encryption ensures data sent between a web browser and a web server is secure, making it ideal for sensitive transactions, such as online shopping or online banking.

IMAP (Internet Message Access Protocol) is used for email clients that want to keep messages synchronized between the email server and the client. It allows you to create folders, organize messages, and keep the structure consistent on the server.

Additive Increase Multiplicative Decrease (AIMD) is a congestion control mechanism used in TCP. It involves the sender reducing its transmission rate upon detecting network congestion to alleviate network congestion and ensure fair bandwidth usage among competing flows.

Organizations use Network Address Translation (NAT) to enhance security by hiding internal IP addresses from external networks. NAT helps protect internal networks from direct exposure to the internet, making it more difficult for malicious actors to target internal devices.

CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is a mechanism that helps alleviate the issue of data collisions in Ethernet networks. It allows devices to sense the carrier on the shared medium before transmitting data, reducing the likelihood of collisions.

The "TIME_WAIT" state in a TCP connection is a necessary part of the connection termination process. It allows any delayed or out-of-order packets from the previous connection to be received and processed, ensuring that all data is successfully exchanged before the connection is fully closed. This prevents data from different connections using the same port from being mixed up. It is not primarily for security or managing the number of active connections, but rather for ensuring data integrity during termination.

The primary purpose of a firewall in network security is to control and monitor network traffic. Firewalls are designed to filter and manage incoming and outgoing traffic, allowing or denying access based on predefined security rules. They are vital for network security and help prevent unauthorized access and data breaches.