The following port numbers are unofficial list of commonly used for linux/unix based servers.
| Port Number | Protocol | Function |
|---|---|---|
| 21 | TCP | FTP (File Transfer Protocol) |
| 22 | TCP/UDP | SSH (ssh,scp copy or sftp) |
| 23 | TCP/UDP | Telnet |
| 25 | TCP/UDP | SMTP (for sending outgoing emails) |
| 43 | TCP | WHOIS function |
| 53 | TCP/UDP | DNS Server (Domain name service for DNS requests) |
| 67 | UDP | DHCP Server |
| 68 | TCP | DHCP Client |
| 70 | TCP | Gopher Protocol |
| 79 | TCP | Finger protocol |
| 110 | TCP | POP3 (for receiving email) |
| 119 | TCP | NNTP (Network News Transfer Protocol) |
| 143 | TCP/UDP | IMAP4 Protocol (for email service) |
| 194 | TCP | IRC |
| 389 | TCP/UDP | LDAP (light weight directory access) |
| 443 | TCP | Secure HTTP over SSL (https) |
| 465 | TCP | Secure SMTP (email) using SSL |
| 990 | TCP/UDP | Secure FTP using SSL |
| 993 | TCP | Secure IMAP protocol over SSL (for emails) |
| 1433 | TCP/UDP | Microsoft SQL server port |
| 2082 | TCP | Cpanel default port |
| 2083 | TCP | Cpanel over SSL |
| 2086 | TCP | Cpanel Webhost Manager (default) |
| 2087 | TCP | Cpanel Webhost Manager (with https) |
| 2095 | TCP | Cpanel Webmail |
| 2096 | TCP | Cpanel secure webmail over SSL |
| 2222 | TCP | DirectAdmin Server Control Panel |
| 3306 | TCP/UDP | MySQL Database Server |
| 4643 | TCP | Virtuosso Power Panel |
| 5432 | TCP | PostgreSQL Database Server |
| 8080 | TCP | HTTP port (alternative one for port 80) |
| 8087 | TCP | Plesk Control Panel Port (default) |
| 8443 | TCP | Plesk Server Control Panel over SSL |
| 9999 | TCP | Urchin Web Analytics |
| 10000 | TCP | Webmin Server Control Panel |
| 19638 | TCP | Ensim Server Control Panel |
Source: http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
