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Network Ports Cheat Sheet
Interactive reference of common TCP/UDP ports for IT certification exams
43 ports total Secure Insecure
| Port | Protocol | Service | Description | Security |
|---|---|---|---|---|
| 20 | TCP | FTP Data | File Transfer Protocol - Data channel for file transfers | Insecure |
| 21 | TCP | FTP Control | File Transfer Protocol - Command/control channel | Insecure |
| 22 | TCP | SSH/SFTP/SCP | Secure Shell - Encrypted remote access, file transfer | Secure |
| 23 | TCP | Telnet | Unencrypted remote terminal access (insecure) | Insecure |
| 25 | TCP | SMTP | Simple Mail Transfer Protocol - Email sending between servers | Insecure |
| 53 | TCP/UDP | DNS | Domain Name System - Resolves domain names to IP addresses | Insecure |
| 67 | UDP | DHCP Server | Dynamic Host Configuration Protocol - Server port | Insecure |
| 68 | UDP | DHCP Client | Dynamic Host Configuration Protocol - Client port | Insecure |
| 69 | UDP | TFTP | Trivial File Transfer Protocol - Simple file transfers (no auth) | Insecure |
| 80 | TCP | HTTP | Hypertext Transfer Protocol - Unencrypted web traffic | Insecure |
| 88 | TCP/UDP | Kerberos | Network authentication protocol (Windows AD) | Secure |
| 110 | TCP | POP3 | Post Office Protocol v3 - Email retrieval (unencrypted) | Insecure |
| 119 | TCP | NNTP | Network News Transfer Protocol - Usenet newsgroups | Insecure |
| 123 | UDP | NTP | Network Time Protocol - Time synchronization | Insecure |
| 137 | UDP | NetBIOS Name | NetBIOS Name Service - Windows name resolution | Insecure |
| 138 | UDP | NetBIOS Datagram | NetBIOS Datagram Service - Connectionless communication | Insecure |
| 139 | TCP | NetBIOS Session | NetBIOS Session Service - Windows file/printer sharing | Insecure |
| 143 | TCP | IMAP | Internet Message Access Protocol - Email retrieval (unencrypted) | Insecure |
| 161 | UDP | SNMP | Simple Network Management Protocol - Network device monitoring | Insecure |
| 162 | UDP | SNMP Trap | SNMP Trap - Alerts from network devices | Insecure |
| 389 | TCP/UDP | LDAP | Lightweight Directory Access Protocol - Directory services | Insecure |
| 443 | TCP | HTTPS | HTTP Secure - Encrypted web traffic via TLS/SSL | Secure |
| 445 | TCP | SMB | Server Message Block - Windows file sharing (direct) | Insecure |
| 465 | TCP | SMTPS | SMTP Secure - Encrypted email sending (deprecated) | Secure |
| 514 | UDP | Syslog | System Logging Protocol - Centralized log collection | Insecure |
| 587 | TCP | SMTP Submission | SMTP with STARTTLS - Modern email submission | Secure |
| 636 | TCP | LDAPS | LDAP Secure - Encrypted directory services | Secure |
| 993 | TCP | IMAPS | IMAP Secure - Encrypted email retrieval | Secure |
| 995 | TCP | POP3S | POP3 Secure - Encrypted email retrieval | Secure |
| 1433 | TCP | MS SQL | Microsoft SQL Server database | Insecure |
| 1521 | TCP | Oracle DB | Oracle Database default listener | Insecure |
| 1723 | TCP | PPTP | Point-to-Point Tunneling Protocol - VPN (insecure) | Insecure |
| 1812 | UDP | RADIUS Auth | RADIUS Authentication - AAA services | Secure |
| 1813 | UDP | RADIUS Acct | RADIUS Accounting - AAA services | Secure |
| 3306 | TCP | MySQL | MySQL/MariaDB database | Insecure |
| 3389 | TCP | RDP | Remote Desktop Protocol - Windows remote access | Insecure |
| 5060 | TCP/UDP | SIP | Session Initiation Protocol - VoIP signaling | Insecure |
| 5061 | TCP | SIPS | SIP Secure - Encrypted VoIP signaling | Secure |
| 5432 | TCP | PostgreSQL | PostgreSQL database | Insecure |
| 5900 | TCP | VNC | Virtual Network Computing - Remote desktop | Insecure |
| 6379 | TCP | Redis | Redis in-memory database | Insecure |
| 8080 | TCP | HTTP Proxy | HTTP alternate/proxy - Common for web proxies | Insecure |
| 8443 | TCP | HTTPS Alt | HTTPS alternate - Common for web apps | Secure |
🎯 Exam Tips
- • Memorize "well-known" ports (0-1023)
- • Know TCP vs UDP differences
- • Learn secure alternatives (FTP→SFTP, HTTP→HTTPS)
- • Port 443 and 22 are most commonly tested
🔐 Security Note
Ports marked Insecure transmit data in plaintext. Always use encrypted alternatives in production. Common upgrades: Telnet→SSH, FTP→SFTP, HTTP→HTTPS.