You can configure user's Connection Limitation and Data Transfer Limitation here.

Max number of sessions per user account
Specifies the maximum number of concurrent sessions that may be opened from a single user account.
Max sessions per IP
Specifies the maximum number of concurrent sessions that a user may open from a single IP address.
Automatic idle connection timeout
When a client has been idle(No FTP Command) for a specific time, it will be automatically disconnected.
Max download speed per session
Limits the maximum download bandwidth for each individual session. Setting a limit of 0 KB/s means unlimited bandwidth.
Max upload speed per session
Limits the maximum upload bandwidth for each individual session. Setting a limit of 0 KB/s means unlimited bandwidth.
Max download speed for user accounts
Limits the maximum download bandwidth shared between all sessions associated with an individual user account. Setting a limit of 0 KB/s means unlimited bandwidth.
Max upload speed for user accounts
Limits the maximum upload bandwidth shared between all sessions associated with an individual User account. Setting a limit of 0 KB/s means unlimited bandwidth.
Automatic transfer connection timeout (only for FTP protocol)
When a client has been idle(No Data Transfer) for a specific time, it will be automatically disconnected.
SSH Public Key Authentication
WingFTP use the password as the SSH authentication. If you want more secure, you can choose use public key authenticate. There are some option to set as shown.