Network Management Protocols

ICMP (Internet Control Message Protocol)

• Used by network devices to send error messages and operational information.
• Commonly used for ping and traceroute.
• Helps detect unreachable hosts and network problems.
• Does not carry user data.
• No port (IP protocol number 1)

SNMP (Simple Network Management Protocol)

• Used to monitor and manage network devices.
• Uses components such as SNMP Manager, SNMP Agent and Managed Device.
• Helps monitor performance and detect faults.
• Widely used in enterprise networks.
• Ports:
  • 161 (UDP) - Queries
  • 162 (UDP) - Traps

Gopher

• Early Internet protocol used to retrieve files from remote systems.
• Organizes files in a hierarchical menu-based structure.
• Now largely obsolete and replaced by HTTP and FTP.
• Default Port 70 (TCP)

FTP (File Transfer Protocol)

• Used to transfer files between a client and a remote server.
• Allows uploading and downloading of files.
• Commonly used for website management and file sharing.
• Requires username and password authentication.
• Ports:
  • 21 (TCP) - Control
  • 20 (TCP) - Data (active mode)

POP3 (Post Office Protocol v3)

• Email protocol used to retrieve emails from a mail server.
• Downloads emails to the local device.
• Emails are often deleted from the server after retrieval.
• Suitable for accessing email from a single device.
• Ports:
  • 110 (TCP)
  • 995 (TCP) - Secure POP3

Telnet

• Remote access protocol used to connect and control remote systems.
• Allows command execution on a remote machine.
• Uses a client–server model.
• Sends data in plain text, making it insecure.
• Mostly replaced by SSH.
• Default Port: 23 (TCP)

✔ Learning Tip

Use tools like Wireshark to observe network traffic. Seeing how data moves across a network builds strong intuition.