Lightweight Directory Access Protocol (LDAP) is used for accessing and maintaining distributed directory information services, making it suitable for organizations requiring directory services.

Server Message Block (SMB)/Common Internet File System (CIFS) using port 445 is utilized for file sharing, printer sharing, and network communication among devices on a network, such as scanning documents from a networked printer to a shared folder on a server.

Dynamic Host Configuration Protocol (DHCP) is used to automatically assign IP addresses and other network configuration parameters to devices on a network, facilitating easy network management.

Remote Desktop Protocol (RDP), utilizing port 3389, is specifically designed to provide a graphical interface for remotely accessing another machine, offering a full graphical user interface for remote management and operations.

Secure Shell (SSH), using port 22, is widely used for securely accessing network devices and servers via a command line interface. It encrypts the session, providing security for managing devices.

Dynamic Host Configuration Protocol (DHCP) uses ports 67 and 68 to assign IP addresses automatically to client machines on a network. The technician should ensure the DHCP service is operational to resolve the IP address issue.

Lightweight Directory Access Protocol (LDAP), using port 389, is designed for accessing and managing directory services, making it ideal for storing and organizing user account information.

Post Office Protocol 3 (POP3) uses port 110 and is designed for receiving emails from a server to a local email client. While SMTP is used for sending emails, POP3 is the protocol designed for receiving them.

Telnet, operating over port 23, offers a command-line interface for remotely managing devices such as network switches. While it does not encrypt communication, making it vulnerable to interception, it is suitable for use in environments isolated from external threats where encryption is not a primary concern.

Simple Network Management Protocol (SNMP), using ports 161/162, is designed for managing devices like switches and routers on IP networks by gathering and organizing information and configuring devices remotely.

To enable employees to securely access their work desktops remotely, the organization should implement the Remote Desktop Protocol (RDP) using port 3389. RDP provides a secure, encrypted connection for remote desktop access, offering both security and functionality for remote work scenarios.

Post Office Protocol 3 (POP3) is designed for downloading emails from a mail server to a local client. POP3 allows emails to be stored locally, which is suitable for users who need to access their emails offline.

UDP (User Datagram Protocol) is used for simple query-response protocols like SNMP (Simple Network Management Protocol) on port 161. UDP is suitable for applications requiring fast, real-time data without the overhead of establishing a connection, like streaming services.

Trivial File Transfer Protocol (TFTP) uses port 69 and is designed for simpler, more efficient file transfers than FTP, especially suitable for transferring small files across a network with less overhead.

Port 25 is used by Simple Mail Transfer Protocol (SMTP), which is responsible for sending emails. Ensuring this port is open is crucial for the email client’s ability to send emails.

Port 80 is used by Hypertext Transfer Protocol (HTTP), which is the foundation of data communication for the World Wide Web, making it essential for browsing the web.

Internet Mail Access Protocol (IMAP) on port 143 allows users to access their emails from multiple devices while keeping the emails stored on the server, making it ideal for users who access their email from various locations.

Secure Shell (SSH) on port 22 is used for securely accessing and managing network devices remotely. SSH encrypts the data transmitted, ensuring secure management of network devices.

Domain Name System (DNS) primarily uses port 53 to translate domain names into IP addresses. This port is crucial for resolving domain names, which is necessary for accessing websites.

Secure Shell (SSH) is a protocol used to securely access and manage a remote server. SSH provides a secure channel over an unsecured network by using encryption, making it the preferred choice for secure remote server management.

Simple Mail Transfer Protocol (SMTP) using port 25 is used for sending emails, including sending scanned documents from a printer to email recipients.

Simple Network Management Protocol (SNMP) is used for managing devices on IP networks. It allows for collecting information from, and configuring, network devices, such as routers and switches.

Port 443 is used by HTTPS, which secures web communication through encryption. It is essential for secure web applications requiring encrypted data transmission.

Secure Shell (SSH) is not only used for secure access to remote servers but also supports secure file transfers via SCP or SFTP, making it the best choice for secure file transfers between servers.