What is the connection problem in ProFTPd?

Question

Debian

Good afternoon.
I already wrote a question in general on linux ( https://toster.ru/q/382274) - I suffered for 2 days, got a password for root, rebooted the server, restarted the service, checked the place, climbed the config - until I solved the problem. Who can will prompt what it is possible to look still directly on the server?
The essence of the problem:
The debian 6 squeeze server is rented from a hoster without administration. The server has only the ProFTPd FTP service, and now, about a week ago, the normal connection to FTP disappeared. Total and filesize (I try both in passive and active mode) - they don’t want to connect, occasionally - a connection passes every half an hour, a list of files located on ftp is displayed, but when I try to upload / download the connection hangs and then breaks. Through cmd I connect to ftp without problems, and copy the files. While I do not understand what could be the problem, I will be grateful for any tips).
Upd: Not relevant anymore - there was a problem in the network. Thank you.

Answer 1

The problem was in balancing on the router - when CEF was running, it dropped packets when connecting via FTP through both channels with an incomprehensible pattern - because of this, the problem turned out. I tied the connection to the ftp server through a specific link with a policy - everything went with a bang from any channel.

Answer 2

If through cmd passes, try to change the client. I'm already used to connecting ftp servers through TotalCommander.