Difference between FTP payload Data and simply chopping a file into payload size

[ahm_irf]

what is the difference between simple FTP payload data and chopping a file into payload size. Both contains same data.

do FTP changes data in any means during the transfer which later handles in application or transport layer. I am using VSFTP in fedora 6.

[wje_lf]

A file which is transferred from one host to another via ftp has exactly the same length and content, with these considerations:

1. Be sure you transfer the file in binary mode, not ascii mode.
2. If a file has "holes", these holes will be transformed into NUL bytes. A file hole exists in certain files when there would ordinarily be NUL bytes in the first place, so this should not affect you. (If you're not familiar with file holes, chances are you don't need to worry about this.)

Hope this helps.

[ahm_irf]

do FTP or other protocols pad zeors at the end of the packets........because I used FTP to transfer a file and a capture those packets.....when I have extracted the payload from packets I found out that the actual payload is of just 30 bytes out of 1448 bytes and rest is padded with zeros

any idea why this is happening .....

[wje_lf]

Find your answer here.