Port Number
20/21
What is FTP/File Transfer Protocol
67/68
DHCP/Dynamic Host Configuration Protocol
161/162
SNMP/Simple Network Management Protocol
22
What is SSH/Secure Shell
80
HTTP/Hypertext Transfer Protocol
389
LDAP/Lightweight Directory Access Protocol
23
What is Telenet
110
POP3/Post Office Protocol 3
443
HTTPS/Hypertext Transfer Protocol Secure
25
SMTP/Simple Mail Transfer Protocol
137/139
445
SMB/CIFS, Server Message Block/Common Internet File System
53
DNS/Domain Name System
143
IMAP/Internet Mail Access Protocol
3389
RDP/Remote Desktop Protocol