As per the MCSE guide to Windows XP Professional second edition pg. 317 the answer is FTP.
File sharing commonly utilizes several ports, with TCP port 21 being designated for FTP (File Transfer Protocol) and TCP port 22 for SFTP (Secure File Transfer Protocol) and SCP (Secure Copy Protocol). Additionally, TCP port 445 is used for SMB (Server Message Block) in Windows environments. Other ports, like TCP port 137-139, can also be involved in file sharing, especially for older systems using NetBIOS over TCP/IP.
tcp based protocols,internet protocol,sometimes file transfer protocol also supported by tcp wrappers. tcp is reliable and connection oriented.
The protocol is FTP and the port number 21 conquerorthecomputer.blogspot.com
TCP
The SFTP port is used for secure logins, secure file transfer and port forwarding. It can be found on port 22 of the TCP protocol. The name of this port stands for Secure File Transfer Protocol.
TCP/IP is the standard default.
You can use either TCP or UDP. If you need reliable connection use TCP otherwise UDP.
Ftp is a file transfer protocol use with TCP/IP Protocol to transfer files directly to a server through the internet.
tcp/ip
That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.
TCP is a sub-protocol within the IP protocol. Think of TCP as one of the instruments in a band.
TCP (also sometimes called TCP/IP)