TCP/UDP Port Numbers

Port Number

100

20/21

What is FTP/File Transfer Protocol 

200

22

What is SSH/Secure Shell

300

23

What is Telenet

400

25

SMTP/Simple Mail Transfer Protocol 

500

53

DNS/Domain Name System

Port Number 2

100

67/68

DHCP/Dynamic Host Configuration Protocol 

200

80

HTTP/Hypertext Transfer Protocol  

300

110

POP3/Post Office Protocol 3

400

137/139

NetBIOS/Network Basic Input/Output System, NetBT/NetBIOS over TCP/IP

500

143

IMAP/Internet Mail Access Protocol 

Port Number 3

100

161/162

SNMP/Simple Network Management Protocol 

200

389

LDAP/Lightweight Directory Access Protocol

300

443

HTTPS/Hypertext Transfer Protocol Secure

400

445

SMB/CIFS, Server Message Block/Common Internet File System

500

3389

RDP/Remote Desktop Protocol