FlashFXP How do I set the active access mode?

We all know that FTP has two access modes, then how do we set these two access mode? Please see below for more information

First, FTP compatible

1, open the Control Panel--click Internet Options

2. Select Advanced tab

3, find the option. Use Passive FTP (compatible with firewalls and DSL modems)---will be checked out, click OK.

Second, FLASHFXP set up active access mode

1, open the software, click the option--> select parameter settings

2, find the agent will use the passive mode of the hook removed, click OK.

Third, what is the FTP active mode and passive mode

FTP is the abbreviation of File Transfer Protocol, FTP transport protocol has many advantages, so the transfer of files using the FTP protocol many software, FTP protocol use of the port is 21 (also known as the control port), in fact, there is a data port 20, according to the different ways of FTP work, data port is not all 20, Active mode passive mode uses a different data port, and I'll take a step-by-step approach to the difference between active FTP mode and passive FTP mode:

1, what is active FTP

Active mode of FTP work: the client from an arbitrary unprivileged port n connected to the FTP server command port, that is, 21 port. The client then starts listening on the port n+1 and sends the FTP command "Port n+1" to the FTP server. The server then connects to the client-specified data port (n+1) from its own data port (20).

For the firewall in front of the FTP server, you must allow the following traffic to support active ftp:

1 any port greater than 1024 to the 21 port of the FTP server. (client-initiated connection)

2 The FTP server's 21 port to the port greater than 1024. (server responds to client's control port)

3 The FTP server's 20 port to the port greater than 1024. (Server-side initialization data connects to the client's data port)

4) greater than 1024 port to the FTP server 20 port (the client sends an ACK response to the server's data port)

2, what is passive FTP

In order to solve the problem that the server initiates the connection to the customer, people developed a kind of different FTP connection way. This is called passive mode, or PASV, which is enabled when the client notifies the server that it is in passive mode.

In passive mode FTP, both the command and data connections are initiated by the client, which resolves the problem of the inbound connection of the data port from the server to the client being filtered by the firewall.

When an FTP connection is turned on, the client opens two arbitrary, non privileged local ports (N > 1024 and n+1). The first port connects to the server's 21 port, but unlike active FTP, the client does not submit the Port command and allows the server to go back and forth to its data port, instead submitting the PASV command. The result is that the server will open an arbitrary unprivileged port (P > 1024) and send the port p command to the client. The client then initiates a connection to port p from the local port n+1 to the server to transmit the data.

For a server-side firewall, the following traffic must be allowed to support passive ftp:

1 from any port greater than 1024 to the server's 21 port (client initiated connection)

2 The server's 21 port to any port greater than 1024 (the server responds to the client's control port connection)

3 from any port greater than 1024 to the server (client initialization data is connected to any port specified by the server)

4 The server's greater than 1024 port to the remote port greater than 1024 (the server sends an ACK response and data to the client's data port)

The above explanations for active and passive FTP can be summarized in the following two points:

1 Active ftp:

Command connection: Client >1024 port-> Server 21 Port

Data connection: Client >1024 port <-server 20 port

2) Passive ftp:

Command connection: Client >1024 port-> Server 21 Port

Data connection: Client >1024 port-> server >1024 Port

3, Active mode FTP and passive mode FTP advantages and disadvantages:

Active FTP is good for the management and security of FTP servers, but it is bad for client management. Because the FTP server attempts to establish a connection with the client's high random port, the port is likely to be blocked by the client's firewall. Passive FTP is advantageous to the management of FTP clients, but not to server-side management. Because the client wants to establish two connections to the server, one of them is connected to a high random port, and the port is likely to be blocked by the server-side firewall.