Here is a list of common TCP/IP ports for reference when conducting a penetration test:

Common TCP/IP Ports
Port Type Usage
20 TCP FTP Data
21 TCP FTP Control
22 TCP|UDP Secure Shell (SSH)
23 TCP Telnet
25 TCP Simple Mail Transfer Protocol (SMTP)
42 TCP|UDP Windows Internet Name Service (WINS)
53 TCP|UDP Domain Name System (DNS)
67 UDP DHCP Server
68 UDP DHCP Client
69 UDP Trivial File Transfer Protocol
80 TCP|UDP Hypertext Transfer Protocol (HTTP)
110 TCP Post Office Protocol (POP3)
119 TCP Network News Transfer Protocol (NNTP)
123 TCP Network Time Protocol (NTP)
135 TCP|UDP Microsoft RPC
137 TCP|UDP NetBIOS Name Service
138 TCP|UDP NetBIOS Datagram Service
139 TCP|UDP NetBIOS Session Service
143 TCP|UDP Internet Message Access Protocol (IMAP)
161 TCP|UDP Simple Network Management Protocol (SNMP)
162 TCP|UDP Simple Network Management Protocol (SNMP) Trap
389 TCP|UDP Lightweight Directory Access Protocol (LDAP)
443 TCP|UDP Hypertext Transfer Protocol over TLS/SSL (HTTPS)
445 TCP Server Message Block (SMB)
636 TCP|UDP Lightweight Directory Access Protocol over TLS/SSL (LDAPS)
873 TCP Remote File Synchronization Protocol (rsync)
993 TCP Internet Message Access Protocol over SSL (IMAPS)
995 TCP Post Office Protocol 3 over TLS/SSL (POP3S)
1433 TCP Microsoft SQL Server Database
3306 TCP MySQL Database
3389 TCP Microsoft Terminal Server/Remote Desktop Protocol (RDP)
5800 TCP Virtual Network Computing (VNC) Web Interface
5900 TCP Virtual Network Computing (VNC) Remote Desktop