Oh, I personally have seen an FTP protocol, and it's not simple at all. The actual data transfer is set up in a completely bonkers way, be it in active or passi

Oh, I personally have seen an FTP protocol, and it's not simple at all. The actual data transfer is set up in a completely bonkers way, be it in active or passive mode. Even if you really, really need two separate connections for commands and for data (spoilers: you actually don't), why not have it done like this: * client connects to ftp-server:22 > STOR ~/newfile.txt <CR><LF> < 227 server-generated-magical-cookie-nonce <CR><LF> * client again connects to ftp-server:22 > DATA server-generated-magical-cookie-nonce <CR><LF> < 225 <CR><LF> > ...binary data follows And never mind all the cruft needed to support OSes that pre-date UNIX or, in fact, TCP's wide adoption. Seriously, 99% of the time all the upload functionality you want is equivalent to <newfile.txt ssh ftp-server 'cat >newfile.txt' The 1 remaining percent is upload resumption.