import ftplib, sys 
ftp1 = ftplib.FTP('127.0.0.1', 'book', 'bookpw') 
ftp1.cwd('/Dir') 
ftp2 = ftplib.FTP('www.holdenweb.com', 'bookuser', 'bookpw') 
ftp2.cwd('/public') 
sock1 = ftp1.transfercmd('RETR a.zip') 
sock2 = ftp2.transfercmd('STOR b.zip') 
 
flen = 0                             
while 1: 
    block = sock1.recv(1024)         
    if len(block) == 0:              
        break 
    flen += len(block)               
    while len(block) > 0:            
        sentlen = sock2.send(block)  
        block = block[sentlen:]      
 
print 'Transferred', flen, 'bytes' 
 
sock1.close() 
sock2.close() 
ftp1.quit() 
ftp2.quit()