Wondering if this may be related to IP Address Banning change for [JIRA-CS-77/Ticket #5927].
Idle Connection Timeout: enabled, 2 mins
Kick User after x bad cmds: enabled, 7
Ban access from IP once this happens: enabled
Block anti-timeout schemes: enabled
Enable Flood Protection: enabled, 25 conns in 30s
Enable User/Pwd HackingProtection: enabled, 5 attempts in 10s
When an FTP client is kicked due to idle timeout, they are now getting their IP Auto Banned. This is NEW, previously idle timeouts would not cause IP auto Banning. I'm not sure this change makes sense as it means legit users who happen to timeout (e.g. bad script) get banned until manually un-banned.
If it helps, this seems to be more likely to affect clients who have a second non-idle session active at the same time.
I was unable to reproduce that behavior in testing using the specified settings. Can you please set logging to debug (logging, log settings tab, information level), clear any banned IP addresses, reproduce the issue and forward the log file as an attachment? I'll take a look at what's going on. Please also include the username in question (to make the log search easier).