Port is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service. At the software level, within an operating system,
ex :
Protocol | Port Number |
FTP | 21 |
SSH | 22 |
Telnet | 23 |
SMTP | 25 |
DNS | 53 |
DHCP | 66/67 |
HTTP | 80 |
POP | 110 |
IMAP | 143 |
SNMP | 161 |
HTTPS | 443 |
MYSQL | 3306 |
RDP | 3389 |