Two ways to log in FTP_ Web surfing

In order to share resources, many enterprise networks have set up an FTP server. Generally these FTP servers are connected through the network firewall or port access to the public network, it will encounter the user can not log on to the FTP server problem. The emergence of these problems, in addition to the user's operation errors, mainly with the network firewall strictly control the port and complex network environment. Below, Dr. E on this issue to tell you how to choose the FTP server login mode. One, the FTP mode of work to completely solve the user can not log on the FTP server problem, you must understand the FTP protocol working mode. The FTP protocol has two working modes: port mode and PASV mode, port is an active mode and PASV is passive mode, relative to the server. Small knowledge: FTP (file Transfer Protocol Files Transfer Protocol) service is a service based on TCP protocol, used to transfer files between computers, through which users can obtain resources on the Internet. FTP provides logins, directory queries, file operations, and other session-control functions. It is also used when uploading or downloading Web site files. Port mode: Port mode establishes the data link channel is initiated by the FTP server side, the FTP server uses 20 ports to connect the client's one more than 1024 port. PASV mode: The PASV mode of the data transmission link is established by the FTP client, which uses a port greater than 1024 to connect more than 1024 of a port on the server. When a user logs on to FTP, the server should use port 21 (which can also use port 20 and some unfixed ports greater than 1024), and the client should use a port greater than 1024. Because the network firewall to the port strict control and complex network environment, so it is very easy to have the user can not log on the FTP server problem. Second, the choice of mode in order to successfully log on to the FTP server, the client must correctly set up login using PASV or port mode. 1. Use intranet IP address when the client uses the port login method, the FTP server will not be able to connect the client to establish the data link. Because the client does not have a public network IP address, in this case, the client must use the Pasv login method. This is a lot of intranet users can not log on to the FTP server is an important reason. 2. Use the public network IP address when the client uses the Pasv login method, the client sends the connection request to the server, establishes the data link channel, then may successfully log on the FTP server. If you use the port login method, when the data link channel is established, the server sends a connection request to the client, at which point the connection request is blocked by the firewall, unless opening a high-end port greater than 1024. For the general user, directly determine which type of login to use some difficulties, you may wish to use a way to log on to the FTP server, if not, and then select anotherKind of way. Third, the choice of login mode in most of the FTP client software login mode selection, only see the PASV mode (passive mode), this is because the FTP login method only port and PASV two kinds, using PASV login means to cancel the port login mode. 1. In IE to switch login mode Internet Explorer by default port login method, to use PASV login method is very simple. In the IE main window, click "Tools →internet Options" to switch to the "Advanced" tab, select the "Use Passive FTP" option, click "OK" button. 2. Switch logins in POWERFTP in the Powerftp main window, click "Tools → options", in the Pop-up Options dialog box, click the "Agent" option, in the box on the right to select the "Use PASV mode" option, and finally click the "OK" button, so you can use the PASV login mode, If you do not select this item, you are using the port login method. Other FTP client software settings are basically the same, there is no other example.