p11 5.2.3

Network Ports

• Unique numbers assigned by the operating system for different types of network traffic.

• Help direct information based on its type.

• Reserved ports exist for common services (e.g., email, file transfer).

• Some ports are only assigned temporarily; they revert to unassigned after use.

• Closed ports prevent access (user cannot connect).

Port Forwarding

• Process of redirecting network traffic from one address to another.

• Example: Port 3389 used for Remote Desktop Protocol (RDP).

• Requires proper setup on both computers and the router (both doors must be unlocked).

Common Network Ports and Protocols

• Port 21: File Transfer Protocol (FTP) - Standard for transferring files.

• Port 22: Secure Shell (SSH) - Provides secure communication for system access.

• Port 25: Simple Mail Transfer Protocol (SMTP) - Traditional service for sending email (now deprecated for some uses).

• Port 53: Domain Name System (DNS) - Resolves domain names to IP addresses.

• Port 80: Hypertext Transfer Protocol (HTTP) - Standard for web communication.

• Port 110: Post Office Protocol v3 (POP3) - Used by email programs for incoming mail.

• Port 143: Internet Message Access Protocol (IMAP) - Another protocol for retrieving emails.

• Port 443: Hypertext Transfer Protocol Secure (HTTPS) - Secured version of HTTP, encrypts communication for web traffic.