Multiple Passive connections to vsftpd server

I am trying to upload multiple files simultaneously. after establishing a data connection in passive mode, my client sending another "pasv" request to the vsftp server to get server and port value. so that i can connect to the vsftpd using the new set of port and ip values. but server(vsftpd) is not responding for this second pasv command.

here is the sequence of commands my client is sending after login.

PASV ------> to server

227 entering passive mode (x,x,x,x,d,d) <------ from server

STOR xyz.txt -------> to server

150 OK to send data <------- from server

...... creating socket and conn开发者_运维问答ecting to the server using x,x,x,x,d.d.

After that again i am sending pasv to get another port for second connection PASV -------> to server

But server is not sending anything back.

can anyone help on this issue.

thanks -Alexander

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You can only have one pair of command connection,data connection to an FTP server. That is, you cannot set up a 2 data connections to an FTP server by issuing the PASV command twice. You'll have to set up another FTP command connection if you want to do another data connection as well.