Classic Ports to know

# 22 = SSH (Secure Shell) - log  into a Linux instance

# 21 = FTP (File Transfer Protocol)

# 22 = SFTP (Secure File Transfer Protocol) upload files using SSH

# 80 = HTTP - access unsecured websites

# 443 = HTTPS - access secured websites

# 3389 = RDP (Remote Desktop Protocol) - log into a windows instance