1. TCP/IP (Transmission Control Protocol/Internet Protocol):

   • Function: The foundational suite for internet communication, TCP ensures reliable, connection-oriented data delivery, while IP handles addressing and routing.

2. HTTP/HTTPS (Hypertext Transfer Protocol/Secure):

   • Function: HTTP is used for web page retrieval, while HTTPS adds a layer of security with encrypted communication, crucial for secure online transactions.

3. FTP (File Transfer Protocol):

   • Function: Facilitates the transfer of files between computers on a network. It’s commonly used for uploading website content and large file exchanges.

4. DNS (Domain Name System):

   • Function: Translates human-readable domain names into IP addresses, enabling users to access websites using names instead of numerical IP addresses.

5. SMTP (Simple Mail Transfer Protocol):

   • Function: Manages the sending of emails between servers. It’s the protocol responsible for the delivery of emails over the internet.

6. IMAP/POP3 (Internet Message Access Protocol/Post Office Protocol):

   • Function: Both protocols are used for retrieving emails from servers to clients. IMAP allows for synchronization across multiple devices, while POP3 downloads emails to a single device.

7. SSH (Secure Shell):

   • Function: Provides secure remote access and file transfer over an insecure network. It encrypts the data during transmission, ensuring confidentiality.

8. SNMP (Simple Network Management Protocol):

   • Function: Monitors and manages network devices, providing a standardized way for devices to communicate information about their state and performance.

9. VoIP (Voice over Internet Protocol):

   • Function: Transforms voice signals into data packets for transmission over the internet. Enables voice communication over IP networks, including the internet.

10. ICMP (Internet Control Message Protocol):

    • Function: Used for error reporting and diagnostics in IP networks. ICMP sends messages between devices to indicate issues or request information.

11. ARP (Address Resolution Protocol):

    • Function: Maps an IP address to a physical MAC address on a local network. Essential for the proper functioning of Ethernet networks.

12. DHCP (Dynamic Host Configuration Protocol):

    • Function: Automates the assignment of IP addresses and other network configuration parameters to devices on a network, simplifying network administration.

Understanding these protocols and their functions is fundamental for network engineers in designing, implementing, and maintaining robust and secure networks.