FTP
FTP is an older protocol for accessing information resources that was
the primary standard before HTTP. It provides a structure and
interface that resembles a file system more closely than HTTP does.
This makes it better for uploading information to a web site, since it
is always possible to get directory listings through FTP. FTP is still
often used for downloading programs.
FTP cannot be run encrypted. It is however possible to use the port
forwarding features of SSH to run FTP encrypted, if SSH is installed
both in the client and server. FTP uses two network connections, it is
quite easy to make the command channel encrypted while it is hard to
ensure that the data channel is encrypted. Since all passwords are
sent through the command channel it is often enough to encrypt it.
Creating an FTP Port
You create a FTP port by choosing the FTP protocol and a port number,
the default is 21. After that, the following server variables can be
used to control the behavior of the FTP service:
- Allow anonymous FTP
-
Whether to allow anonymous ftp users
or not. If allowed it will be possible to log on as anonymous
or ftp with any password, or get information with no user
authenticating at all.
- Allow FTP guest users
-
If allowed the FTP protocol
module will allow accesses by users who were not authenticated
correctly, according to the current user database. The main reason for
this option is that the whole web site might not use the same
authentication system. Users may, for instance, use .htaccess
files with their own user and password database to control the access
to their own pages.
When using this option users will not know right away if they typed
in their password correctly. Any password will do, since the actual
authentication will not take place until they try to access restricted
pages. This is more in line with how HTTP works than how FTP usually
works.
- Allow named FTP
-
If set, the FTP protocol module will
allow authenticated users to log on.
- FTP user session limit
-
Limits the number of
simultaneous FTP sessions a user can have. By default 0, which means
an unlimited number of sessions.
- Shell database
-
If set, the FTP protocol module will
use the shell database together with the user database to determine
whether the user should have FTP access. This way, Challenger becomes
more compatible with the standard Unix FTP daemons. Entering an empty
value will disable the check.
Using FTP
For Challenger there is no difference between a FTP and a HTTP
request. When used for uploading, an FTP upload will be equivalent to
doing an HTTP PUT. Whether uploading will be allowed or not is up to
the file system module used. The normal Filesystem
module contains an option Handle the PUT method which
controls if it will be possible to upload files or not.
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