FTP - Data (File Transfer Protocol - Data) : TCP Port 20 - FTP Data is used to transfer data from a server or transfer data to a server (e.g., uploading a Web page file to a server).

FTP - Control (File Transfer Protocol - Control) : TCP Port 21 - FTP Control is used to open a connection to the FTP server.

SSH (Secure Shell) : TCP Port 22 - SSH is a network protocol that allows data to be exchanged over a secure channel between two computers.

Telnet (Telecommunication Network) : TCP Port 23 - A terminal emulation program to remotely control Web servers.

SMTP (Simple Mail Transfer Protocol) : TCP Port 25 - SMTP is a protocol used for sending e-mail messages between servers.

DNS (Domain Name Service) : Port 53 - An Internet service that translates domain names into IP addresses.

DHCP (Dynamic Host Configuration Protocol) : udp/67 - Automatically assigns IP addresses and network configuration information. The client computer requesting the address from the DHCP server sends the DHCP request to the server over udp/67 using a source of udp/68.

HTTP (Hypertext Transfer Protocol) : TCP Port 80 - HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to commands.

POP3 (Post Office Protocol 3) : TCP Port 110 - POP3 is a protocol used to retrieve e-mail from a mail server.

IMAP (Internet Message Access Protocol) : TCP Port 143 - Used for retrieving e-mail messages. Successor to POP3, IMAP4 is similar, but supports server-based repositories of sent mail and other specialized folders.

HTTPS (Hypertext Transfer Protocol over Secure Socket Layer) : TCP Port 443 - HTTPS is a Web protocol that encrypts and decrypts page requests and pages returned by the server.

RDP (Remote Desktop Protocol) : Port 3389