Intranet FTP setup-two FTP transmission modes

The following is my personal experience. If you make a mistake, please point it out .! Original Author: smiling assassin Www.OneTian.com <reprinted please keep this line>

Intranet FTP setup-two FTP transmission modes

First, let's talk about the environment. The server is in the Intranet, and the external ing is, 85. There are 7 ports in total ,.!
Among them, 21 is the FTPServer connection end, 80 is the IIS Web occupation, and 85 is the Terminal Services occupation.
There are only four externally available ing ports available at and, and the FTP server uses Serv-u ftp V6.4.

After the server is successfully built using Serv-U, login is successfully created in DOS mode using the FTP. EXE that comes with the system!
150 Opening ASCII mode data connection for/bin/ls is displayed when you view the dir in the execution file.
Then the cursor stops and the server will see a connection timeout reflection. DOS mode false dead no response ,.!

After the FTP tool is changed, FLASHXP is used for connection and the 227 Entering Passive Mode (192,168, 18,) appears)
Then the response times out! Connect to LEAPFTP again. The same prompt is displayed, and the connection timeout is returned ,.!

First GOOGLE ,.! It is learned that 227 is a time-out caused by the failure to establish a transmission connection after entering the passive mode ,.!

Then GOOELE works in two common FTP working modes: PORT and PASV, which are active and passive ,.!

The differences between PORT and PASV are as follows:
The PORT (active) connection process is: the client sends a connection request to the ftp PORT of the server (21 by default,
The server accepts connections. The server sends connection requests to the idle port of the client and establishes a data link to transmit data.

That is to say, when the client opens a port, the server can connect to the port to establish a connection.

Pasv (passive) connection process: the client sends a connection request to the ftp port of the server (21 by default,
The server accepts connections. The client sends connection requests to the idle port of the server and establishes a data link to transmit data.

That is to say, when the server opens a port, the client can connect to the port to establish a connection.

Therefore, it is best to select the active PORT mode for transmission in the Intranet environment ,.! You can also select pasv. Of course, you need to map it out ,.!

Set the pasv port in Serv-U to the port you mapped ,.!

Let's talk about the specific settings of pasv transmission, and talk about PORT ...!

Local server --> Settings --> advanced --> PASV port range ,.! <Here I fill in 81-84, because I only map the available ones, up to 50 ports.>

Save the settings, restart Serv-U, and connect again ,.! The connection is successful!

[Right] PASV
[Right] 227 Entering Passive Mode (192,168)
[Right] opening data connection IP: 124.207.144.18 port: 81
[Right] MLSD
[Right] 150 Opening BINARY mode data connection for MLSD.
[To the right] 226 Transfer complete.
[Right] list completed: 768 bytes in 1.01 seconds (0.7 KB/second)

Upload test.txt and access www.onetian.com/test.txt with the domain name ,.!

In this way, our PASV connection is connected successfully and can be uploaded or downloaded at will ,.!

This is a PASV connection to facilitate client connection in the Intranet environment .!

PORT mode usage .,!

This has great limitations and requires clients to be in the Internet environment .! The server can connect to the port to establish a connection.

The PASV mode above is recommended because both the server and client are in the Intranet environment ,!

Not all FTP tools support PORT mode. Here I recommend FlashFXP and LeapFTP .,!

These two are both very powerful and my favorite ,.! The most important thing is that you can automatically try the replacement mode!

When the PASV mode connection fails, try the PORT mode. In my above test, it is based on the Intranet ,!

Otherwise, I will be able to read the file when I replace the PORT mode in the initial connection ,.!

Serv-U --> Domain --> server --> Settings --> advanced check to allow passive mode application! Restart Serv-U...

LeapFTP --> options --> preference settings --> General --> the proxy removes the option used in PASV mode and selects the option to try the alternate connection mode ,.!

Restart LeapFTP and connect again ,! <The premise is that the client must be in an Internet environment,...>

FlashFXP --> Option --> parameter settings --> connection --> select passive mode as the proxy ..

Are you sure you want to save and restart FlashFXP ,.! Connect again ,.! Connection successful ,,.