Network Protocol Ports

Front

Port 20

Back

FTP (Data) - File Transfer Protocol for data transfer

Front

Port 21

Back

FTP (Control) - File Transfer Protocol for control/commands

Front

Port 22

Back

SSH - Secure Shell for encrypted remote login

Front

Port 23

Back

Telnet - Unencrypted remote login

Front

Port 25

Back

SMTP - Simple Mail Transfer Protocol for email sending

Front

Port 53

Back

DNS - Domain Name System for hostname to IP resolution

Front

Port 67

Back

DHCP (Server) - Dynamic Host Configuration Protocol for server

Front

Port 68

Back

DHCP (Client) - Dynamic Host Configuration Protocol for client

Front

Port 80

Back

HTTP - HyperText Transfer Protocol for web browsing

Front

Port 110

Back

POP3 - Post Office Protocol v3 for incoming email