Well known PortsThe Well Known Ports are those in the range 0–1023. On Unix-like operating systems, binding a communications socket to a port in this range requires administrative/root privileges. The following is the list of such ports.

7/TCP,UDP   Echo    
20/TCP         FTP - data    
21/TCP         FTP—control (command)    
22/TCP,UDP Secure Shell (SSH)—used for secure logins, file transfers (scp, sftp) and port forwarding    
23/TCP         Telnet protocol—unencrypted text communications    
25/TCP         Simple Mail Transfer Protocol (SMTP)—used for e-mail routing between mail servers    
43/TCP         WHOIS protocol    
53/TCP,UDP Domain Name System (DNS)    
57/TCP         MTP, Mail Transfer Protocol    
69/UDP        Trivial File Transfer Protocol (TFTP)    
70/TCP        Gopher protocol    
79/TCP        Finger protocol    
80/TCP        Hypertext Transfer Protocol (HTTP)    
88/TCP        Kerberos—authentication system    
107/TCP     Remote TELNET Service[6] protocol    
109/TCP     Post Office Protocol 2 (POP2)    
110/TCP     Post Office Protocol 3 (POP3)    
111/TCP,UDP     Sun Remote Procedure Call    
115/TCP             Simple File Transfer Protocol (SFTP)    
118/TCP,UDP     SQL (Structured Query Language) Services    
123/UDP            Network Time Protocol (NTP)—used for time synchronization    
143/TCP,UDP     Internet Message Access Protocol (IMAP)—retrieving, synchronizing e-mail messages    
156/TCP,UDP     SQL Service    
161/TCP,UDP     Simple Network Management Protocol (SNMP)    
162/TCP,UDP     Simple Network Management Protocol Trap (SNMPTRAP)[9]    
170/TCP             Print-srv, Network PostScript    
177/TCP,UDP     X Display Manager Control Protocol (XDMCP)    
194/UDP            IRC (Internet Relay Chat)    
220/TCP,UDP     IMAP, Interactive Mail Access Protocol, version 3    
389/TCP,UDP     Lightweight Directory Access Protocol (LDAP)    
443/TCP,UDP     Hypertext Transfer Protocol over TLS/SSL (HTTPS)    
445/TCP             Microsoft-DS Active Directory, Windows shares    
445/UDP            Microsoft-DS SMB file sharing    
465/TCP             SMTP over SSL    
513/UDP            Who    
554/TCP,UDP     Real Time Streaming Protocol (RTSP)    
636/TCP,UDP    Lightweight Directory Access Protocol over TLS/SSL (LDAPS)    
873/TCP            Rsync file synchronisation protocol    
989/TCP,UDP    FTPS Protocol (data): FTP over TLS/SSL    
990/TCP,UDP    FTPS Protocol (control): FTP over TLS/SSL    
992/TCP,UDP    TELNET protocol over TLS/SSL    
993/TCP            Internet Message Access Protocol over SSL (IMAPS)    
995/TCP            Post Office Protocol 3 over TLS/SSL (POP3S)