Core issue
This problem occurs when a Cisco VPN client 4.0.5 is used.
The TCP connection resets within a few minutes, while the UDP connection stays alive for the duration of the file transfer, and beyond.
What is FTP?
FTP stands for File Transfer Protocol which provides a simple way to exchange files over the Internet.The main use of FTP is to upload files on the Internet.It works on server-client model.You need to use FTP Client for uploading file over internet or webspace. An FTP Client is an application which you install on your local computer for transferring files.
Resolution
For a workaround, download and upgrade the VPN concentrator software version to 4.7.2.I or later
VPN 3000 Software Version
4.0