The built-in FTP (File Transfer Protocol) Server is an alternative way to transfer files in/out of your router and its attached storage.
Enable FTP Server:
TLS support: Checking this option enables support for TLS-encrypted communication.
FTP Port: Here, you specify the port to be used for communications. (Default: TCP 21)
Anonymous User Access:
This dropdown allows you to choose whether anonymous users are allowed access to the FTP Server and which file rights they are given.
Allow Admin Login: Enables your local system administrator account as a user for the FTP service.
Log FTP requests and responses: The FTP Server will save all FTP activity (logins/logouts/uploads/downloads/etcetera) via the syslog facility to /var/log/messages.
Anonymous Root Directory: This specifies the location at filesystem-level that is visible to anonymous connections.
Public Root Directory: This filesystem location is accessible by any defined FTP user.
Private Root Directory: This filesystem location is accessible only by the owner. It indicates the location of the Root private directory. Each user will have a protected subfolder under this location.
This controls users' ability to do directory listings.
Maximum Users Allowed to Log in: Here, specify the maximum number of logged-in users at one time. Additional users above the limit will be rejected.
Maximum Connections from the same IP: FTP allows a user multiple sessions from the same client IP address. Here, you specify how many simultaneous FTP connections will be allowed from the same user.
Maximum Bandwidth for Anonymous Users: Built-in FTP throttling will limit the amount of bandwidth (upload/download) to this amount for each anonymous user connected.
Maximum Bandwidth for Authenticated Users: Built-in FTP throttling will limit the amount of bandwidth to this amount for each authenticated user.
Idle Timeout: Specifies the timeout period, in seconds, until a user is disconnected due to inactivity.
Limit Connection Attempts: This option works only when FTP is enabled on the WAN. If selected, two new fields will appear where you can define the maximum number of logon attempts within a given time period. Further connection attempts to the FTP Server will be rejected.
Custom configuration: In this field, you can specify advanced parameters.
The underlying software for the FTP Server is Vsftpd (Vs FTP Daemon). vsftpd
It's recommended you consult its official documentation if you plan to enter settings in this field.
This is the area where you define FTP user accounts. User accounts defined here will be given only FTP service rights. No operating system accounts are created.
Username: The ftp user account name.
Password: The ftp user account password.
Read/Write: This is basically full access.
Read only: The user can only browse and download.
View Only: The user can only browse.
Private: The user can only access their own folder (and not the public area).