For completeness,
let's quickly review the packet exchange seen with
an FTP passive mode file upload.
Just like with the download,
the FTP data session has already been established by the time the
STOR command is sent from client to server.
The server grants permission to the client to upload
the file using a 150 response.
FTP is a very polite protocol indeed.
The 48-byte file representing R3's configuration is uploaded using port 28034,
which was the passive port used for this particular file transfer.
Again,
I've drilled into this FTP packet to reveal the contents towards the bottom.
The final TCP acknowledgement indicates the transfer succeeded and now the regular FTP teardown activities occur.