FTP "CREATED" message being issued thousands of times

[mc...@kanjisoft.com]

Hello,

I'm hoping someone could give me an idea on a problem I've been having 
with the FTP server.
The issue is that at some point, FTP server is rapidly issuing many 
thousands of "CREATED" commands, such as the following:

2018-02-12 20:53:51.640 [NioProcessor-27] INFO  
org.apache.ftpserver.listener.nio.FtpLoggingFilter CREATED

This causes the creations of a huge number of TCP connections in a 
CLOSE_WAIT state on the camera side.

 From what I can tell, the CREATED command is the second in a series of 
commands for logging into the FTP server, such as this from my system's 
log:

2018-02-12 20:53:50.828 [pool-18-thread-30] INFO  
org.apache.ftpserver.listener.nio.FtpLoggingFilter RECEIVED: USER XXXX
2018-02-12 20:53:51.640 [NioProcessor-27] INFO  
org.apache.ftpserver.listener.nio.FtpLoggingFilter CREATED
2018-02-12 20:53:51.640 [pool-18-thread-31] INFO  
org.apache.ftpserver.listener.nio.FtpLoggingFilter OPENED
2018-02-12 20:53:51.640 [pool-18-thread-31] WARN  
com.mycompany.service.ImageFtplet connected, user count incremented to: 
23
2018-02-12 20:53:51.640 [pool-18-thread-31] INFO  
org.apache.ftpserver.listener.nio.FtpLoggingFilter SENT: 220 Service 
ready for new user.


But again, it's just the "CREATED" message being issued.

Another important note is that the cameras were all disconnected right 
before this occurred. I think this may be part of normal power cycling 
of the cameras for each "run" of images, but I really don't know what 
the procedure is at the site.

Another run definitely did start, as shown by barcode date, so one 
possibility is the cameras were trying to log in again (although there 
is no "RECEIVED: USER" shown), and since didn't get in, they just keeps 
re-trying at a very rapid pace.

But when I try this on our systems (power-cycling the camera, 
disconnecting the ethernet, etc.), the camera just gets logged in again 
and starts sending images.

So, I've been unable to reproduce this despite trying a variety of 
measures. If anyone could offer suggestions / ideas, I'd be very 
appreciative.