Primary TCP/IP Port Assignments and Descriptions

Port	Assigment	Description
20	FTP	File Transfer Protocol (Data) - The File Transfer protocol provides a mechanism for transferring specific files between network connected computer systems. Transfer is typically performed using the ftp client which provides a range of commands used to connect to a remote server for the purpose of uploading or downloading files. Most modern web browsers also have the ability to browse and downlaod files located on a remote FTP server. FTP uses TCP (rather than UDP) to transfer files so is considered to be a highly reliable tranport mechanism.
21	FTP File Transfer (Control)
22	SSH - Secure Shell
23	Telnet
25	SMTP - Simple mail Transfer Protocol
53	DNS - Domain Name Server
69	TFTP - Trivial File Transfer (UDP based)
80	HTTP - Hypertext Text Transfer Protocol
110	POP3 - Post Office Protocol
119	NNTP - Network News Transfer Protocol
123	NTP - Network Time Protocol
143	IMAP4 - Internet Message Access Protocol, Version 4
161	SNMP - Simple Network Management Protocol
443	HTTPS - Hypertext Transfer Protocol Secure
2049	NFS - Network File System