Overview
This lecture covered well-known networking port numbers, the protocols that use them, and their primary purposes in network communication and management.
File Transfer Protocols
- FTP (File Transfer Protocol) uses TCP ports 20 (data transfer) and 21 (control), supports authentication and file management.
- SFTP (Secure FTP) uses TCP port 22, encrypting file transfers via the SSH protocol.
- TFTP (Trivial File Transfer Protocol) uses UDP port 69 for simple, unauthenticated, fast file transfers.
Remote Access Protocols
- SSH (Secure Shell) uses TCP port 22 for secure, encrypted command-line remote access.
- Telnet uses TCP port 23 for non-encrypted, insecure remote terminal sessions; should be avoided in favor of SSH.
- RDP (Remote Desktop Protocol) uses TCP port 3389 for graphical remote desktop access, mainly on Windows devices.
Email Protocols
- SMTP (Simple Mail Transfer Protocol) uses TCP port 25 (unencrypted) and port 587 (encrypted with TLS) for sending emails.
- IMAP and POP3 are used for receiving emails (not detailed in this lecture).
Domain and IP Configuration Services
- DNS (Domain Name System) uses UDP port 53 for queries and TCP port 53 for large transfers.
- DHCP (Dynamic Host Configuration Protocol) uses UDP ports 67 (server) and 68 (client) for IP address assignment and management.
Web Protocols
- HTTP (Hypertext Transfer Protocol) uses TCP port 80 for unencrypted web traffic.
- HTTPS (HTTP Secure) uses TCP port 443 for encrypted web traffic using SSL/TLS.
Network Time and Management
- NTP (Network Time Protocol) uses UDP port 123 for synchronizing clocks across network devices.
- SNMP (Simple Network Management Protocol) uses UDP port 161 for queries and UDP port 162 for traps/notifications.
Directory and Authentication Services
- LDAP (Lightweight Directory Access Protocol) uses TCP port 389 for directory queries; LDAPS (secure) uses TCP port 636.
File and Printer Sharing
- SMB (Server Message Block) uses TCP port 445 for file and printer sharing, primarily in Windows environments.
Logging and Database Access
- Syslog uses UDP port 514 for centralized logging from network devices.
- Microsoft SQL Server (MSSQL) uses TCP port 1433 for database access.
Voice over IP (VoIP)
- SIP (Session Initiation Protocol) uses TCP ports 5060 (unencrypted) and 5061 (encrypted) for VoIP call setup and management.
Key Terms & Definitions
- Port Number — A logical endpoint for communication, associated with a specific protocol.
- FTP — File Transfer Protocol for transferring files with authentication.
- SFTP — Secure File Transfer Protocol using SSH for encryption.
- DHCP — Dynamic Host Configuration Protocol for automatic IP assignment.
- DNS — Domain Name System for translating domain names to IP addresses.
- SNMP — Simple Network Management Protocol for device monitoring and management.
- LDAP — Lightweight Directory Access Protocol for directory services.
Action Items / Next Steps
- Memorize common protocol port numbers.
- Review related reading on protocol functions and security implications.