Multiple connection
If using standard FTP protocol then ports 20 and 21 would be used.
FTP uses TCP because the file transfer has to be correct.TFTP uses UDP for speed, but not everything will get there.
Generally port 21 is for FTP 22 for FTP using SSH 990 FTP using SSL
Network
Telnet is similar to HTTP and FTP in that all three use the TCP protocol for connection-oriented
FTP; HTTP; DNS (uses both TCP and UDP); several e-mail protocols including POP3, SMTP, IMAP4.
Ftp is a file transfer protocol use with TCP/IP Protocol to transfer files directly to a server through the internet.
netstat
netstat
The number of ports on a computer depends on the type of computer it is. The type of ports they have--for example USB, headphone, or HDMI--also varies greatly from computer to computer.
Open command prompt and type netstatThis will show all ports in use and all ingoing\outgoing connections along with the connection type. TCP, UDP