Proxy’s are software that are found between a client, for example a browser or FTP applications. and a server, typically an Internet site. Their principal function is caching. Practically the proxy memorizes the client’s most frequent requests(in the cache) and renders it available to each time the same request is made. By so doing, each time a client asks for a file already downloaded, it is no longer necessary to connect to the server, but to the proxy, that has the file in its cache. This method obviously improves the download of files of any dimension.
For Linux users the solution could be FROX.
Frox is a transparent FTP Proxy. This means that any clients you have that are behind the proxy will believe that they are connecting to an FTP server as normal, but will actually be connecting to FROX. It also has support for non-transparent connections; In this case the ftp client can connect directly to FROX, but instead of logging in with “username” should log in with “firstname.lastname@example.org”.
On either of these sorts of connections it can do caching of files you download, or converting of data connections from active<–>passive which can make fire_walling rules a lot easier/safer. There is also basic support for running a virus scanner on downloaded files.
- Installing FTP Proxy FROX.
After downloading the frox-0.7.18.tar.gz package use
tar xvfz frox-0.7.18.tar.gz to unpack
cd Move to the newly created directory
./configure –enable-http-cache –enable-local-cache –enable-virus-scan
Configure FROX graphically with Webmin
To configure Frox using the command-line is a difficult task for newbies, so I’ll prefer we use Webmin(Web-based system administration). If you’re new to it, its worth knowing.
Download the webmin-1.350.tar.gz package and unpack
tar -xvzf webmin-1.350.tar.gz
At the end of the installation connect to (with your borwser) http://localhost:10000 Servers section.
* The LOG; The first thing to do is to indicate to the module, The Full path to the Frox server program ; /usr/local/sbin/frox
and the Full path to the Frox configuration file ; /usr/local/etc/frox.conf.
* Networking related Options; To setup parameters relative to your network card, the ports FROX listens to…
* General Options; Here you can setup – who is doing what
* FTP Protocol Options; Here you can edit the FROX behavior that is the type of connection, passive or active and the assigned ports
* Cache and Virus; This is the last passage and its optional. Here you can setup the Cache and select what virus scanner to use, This done you can now run FROX.
* Now run Frox; Before we run FROX, one last thing. We have to configure iptable to direct the traffic. You have to be the administrator to do this
iptable -t nat -A PREROUTING -p tcp -s ip_server_frox
–dport 21 -j REDIRECT â€“to 2121
With these commands we want to draw all traffic on port 21 and give to port 2121 where FROX listens
When all has been correctly installed and we want to make sure FROX is working correctly, the last passage is to download the FROX Suite. If you can download it then your done if not re-control your configuration.