Overview
This lecture reviews well-known network port numbers for common protocols and applications, focusing on their functionalities and security features.
File Transfer Protocols
- FTP (File Transfer Protocol) uses TCP port 20 (data transfer) and TCP port 21 (control), supports authentication, and file management.
- SFTP (Secure FTP) operates over SSH with TCP port 22, providing encrypted file transfers and management.
- TFTP (Trivial FTP) uses UDP port 69 for simple, unauthenticated file transfers, often for device configuration.
Remote Access Protocols
- SSH (Secure Shell) uses TCP port 22 for encrypted remote terminal access.
- Telnet uses TCP port 23 for unencrypted terminal connections, now rarely used because of security risks.
Email Protocols
- SMTP (Simple Mail Transfer Protocol) uses TCP port 25 (plain) and TCP port 587 (encrypted with TLS) for sending email.
- Email reception uses other protocols, commonly IMAP or POP3.
Domain and Address Management
- DNS (Domain Name System) uses UDP port 53 for standard queries and TCP port 53 for large transfers.
- DHCP (Dynamic Host Configuration Protocol) uses UDP ports 67 and 68 to automatically assign IP addresses and manage leases.
Web and Directory Services
- HTTP (Hypertext Transfer Protocol) uses TCP port 80 for unencrypted web traffic.
- HTTPS (HTTP Secure) uses TCP port 443 for encrypted web traffic (SSL/TLS).
- LDAP (Lightweight Directory Access Protocol) uses TCP port 389; LDAPS (secure) uses TCP port 636 for directory access.
Time and Log Management
- NTP (Network Time Protocol) uses UDP port 123 to synchronize clocks across devices.
- Syslog uses UDP port 514 to transport log data to centralized servers.
Network Management
- SNMP (Simple Network Management Protocol) uses UDP port 161 for queries and UDP port 162 for alerts (traps), various versions offer increasing security.
File and Printer Sharing
- SMB (Server Message Block) uses TCP port 445 for file and printer sharing on Windows networks.
Database and Remote Desktop
- MS SQL Server uses TCP port 1433 for database communication via SQL.
- RDP (Remote Desktop Protocol) uses TCP port 3389 to provide remote desktop access.
Voice Over IP (VoIP) Protocols
- SIP (Session Initiation Protocol) uses TCP ports 5060 and 5061 for VoIP call setup/control, video conferencing, and messaging.
Key Terms & Definitions
- FTP — File Transfer Protocol for generic file transfers.
- SFTP — Secure File Transfer Protocol, encrypted via SSH.
- TFTP — Trivial File Transfer Protocol, simple/unauthenticated file transfers.
- SSH — Secure Shell, encrypted command-line access.
- Telnet — Unencrypted terminal access.
- SMTP — Simple Mail Transfer Protocol for sending emails.
- DNS — Domain Name System for name-to-IP resolution.
- DHCP — Dynamic Host Configuration Protocol for automatic IP assignment.
- HTTP/HTTPS — Web protocols for unencrypted/encrypted communication.
- LDAP/LDAPS — Directory access protocols (plain/secure).
- NTP — Network Time Protocol for clock synchronization.
- Syslog — Protocol for centralized log collection.
- SNMP — Network management protocol.
- SMB — Server Message Block for network file/printer sharing.
- MS SQL — Microsoft’s SQL database protocol.
- RDP — Remote Desktop Protocol for remote GUI access.
- SIP — Session Initiation Protocol for VoIP communications.
Action Items / Next Steps
- Review and memorize key port numbers and their associated protocols.
- Practice configuring these protocols in a lab setting.
- Prepare for exam questions on protocol functions and security features.