tftp server and client
PumpKIN is an open source, fully functional, free TFTP server and TFTP client, which implements TFTP according to RFC1350. It also implements block size option, which allows transfer of files over 32MB, as well as transfer size and transfer timeout options described in RFC2348 and RFC2349.
Note that PumpKIN is not an FTP server, neither it is an FTP client, it is a TFTP server and TFTP client. TFTP is not FTP, these are different protocols. TFTP, unlike FTP, is used primarily for transferring files to and from the network equipment (e.g. your router, switch, hub, whatnot firmware upgrade or backup, or configuration backup and restore) that supports using of TFTP server for maintenance, not for general purpose serving downloadable files or retrieving files from the FTP servers around the world.