FTP (File Transfer Protocol) is a well established Internet protocol designed to transfer files (and information about files) across networks using TCP (Transmission Control Protocol). FTP is defined in the Request For Comments 959 document (RFC 959), which can be obtained from the Internet Engineering Task Force.

FTPS is FTP over SSL. There are two incompatible variants of FTPS: explicit and implicit. FTPS explicit is the most recent and most widely used variant. FTPS implicit is older and is generally being phased out. FTP and FTPS explicit can coexist on the same port (usually 21), in fact FTPS explicit connections start out as FTP connections before being switched to SSL. FTPS implicit requires its own dedicated port (usually 990).

The various FTP/FTPS settings that are available to configure CompleteFTP are described below. Note that settings must be saved via the Apply Changes button, otherwise they will be lost.

Setting	Description
FTP enabled	If checked, the FTP protocol is enabled. If not checked, the FTP protocol will not be supported by the server (although FTPS may be enabled, below).
FTPS explicit enabled (standard FTPS)	If checked, the FTPS protocol (explicit mode) is enabled. If not checked, FTPS explicit mode will not be supported by the server. If "FTP enabled" is not checked and FTPS (either implicit or explicit or both) is, then users are forced to use FTPS (i.e. they must connect securely).
FTPS implicit enabled (legacy FTPS)	If checked, the FTPS protocol (implicit mode) is enabled. This is a legacy form of FTPS that is still widely used. If not checked, FTPS implicit mode will not be supported by the server. If "FTP enabled" is not checked and FTPS (either implicit or explicit or both) is, then users are forced to use FTPS (i.e. they must connect securely)./td>
Anonymous logins enabled	If checked, anonymous access is enabled. This means connections can be made by logging in as an anonymous user rather than as a named user with a password.
Max no. of anonymous connections	The maximum number of simultaneous anoynmous connections permitted to the server.
Port for FTP/FTPS explicit	Port that is used for FTP and FTPS in explicit mode. The standard port number for FTP and explicit FTPS is port 21.
Port for FTPS implicit	Port that is used for FTPS in implicit mode. The standard port number for implicit FTPS is port 990.
Listening IP addresses	Lists the IP addresses to listen on for this protocol. All network interfaces can be selected, or individual interfaces selected.
Folder listing format	Format of folder listings being sent back to clients. In the FTP protocol folder listings are sent back to the client as plain text. This setting controls the format of this plain text. This is particularly significant for non-console client applications, which usually parse the directory listings automatically.
Character set	Character set that is used for encoding file-names.
External IP address	In passive (PASV) mode transfers, the server listens on a random port between the minimum and the maximum port numbers specified, waiting for a connection from the client to this port. The server sends the client a reply to the PASV command that provides the IP address to connect to and the port number. This setting allows a hard-coded IP address to be set. If not set, the IP address of the interface that the server is listening on is provided. This setting is required in cases where the IP address of the server is not reachable by clients. For example, the client may need to connect to another IP address that is accessible externally, and a NAT device may direct the connection to the server.
Minimum port number	This is the minimum port number used in passive (PASV) mode. In PASV mode transfers, the server listens on a random port between the minimum and the maximum port numbers specified, waiting for a connection from the client to this port.
Maximum port number	This is the maximum port number used in passive (PASV) mode. In PASV mode transfers, the server listens on a random port between the minimum and the maximum port numbers specified, waiting for a connection from the client to this port.
Clients must supply certificates	This option controls whether or not certificates should be requested from FTPS clients. If they are required then the client must send a certificate that may be validated against the Windows certificate store. This means that either the client's certificate itself, or the certificate of one of its issuers must be in the Windows 'Trusted root certificate authorities' store.
Server certificate	Displays the dialog for controlling the server certificate. A server certificate must be set if FTPS or HTTPS is enabled. The dialog displays the current certificate's properties, and enables a new self-signed certificate to be generated. Also, a certificate signing request (CSR) can be created to send to a certificate authority (CA) to obtain a CA certficate.
Available cipher suites	This setting controls the cipher suites that can be used. Generally, the default is appropriate unless there are special requirements for a particular algorithm.