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File Transfers

Taylor UUCP also allows you to fine-tune file transfers in great detail. At one extreme, you can disable transfers to and from a particular system. Just set request to no, and the remote system will not be able either to retrieve files from your system or send it any files. Similarly, you can prohibit your users from transferring files to or from a system by setting transfer to no. By default, users on both the local and the remote system are allowed to up- and download files.

In addition, you can configure the directories to and from which files may be copied. Usually, you will want to restrict access from remote systems to a single directory hierarchy, but still allow your users to send files from their home directory. Commonly, remote users will be allowed to receive files only from the public UUCP directory, /var/spool/uucppublic. This is the traditional place to make files publicly available; very much like FTP servers on the Internet. It is commonly referred to using the tilde character.

Therefore, Taylor UUCP provides four different commands to configure the directories for sending and receiving files. They are local-send, which specifies the list of directories a user may ask UUCP to send files from; local-receive, which gives the the list of directories a user may ask to receive files to; and remote-send and remote-receive, which do the analogous for requests from a foreign system. Consider the following example:

The local-send command allows users on your host to send any files below /home and from the public UUCP directory to pablo. The local-receive command allows them to receive files either to the world-writable receive directory in the uucppublic, or any world-writable directory below /home. The remote-send directive allows pablo to request files from /var/spool/uucppublic, except for files below the incoming and receive directories. This is signaled to uucico by preceding the directory names with exclamation marks. Finally, the last line allows pablo to upload any files to incoming.

One of the biggest problems with file transfers using UUCP is that will only receive files to directories that are world-writable. This may tempt some users to set up traps for other users, etc. However, there's no way escaping this problem except disabling UUCP file transfers altogether.

Next: Forwarding Up: The Do's and Dont's Previous: Command Execution

Andrew Anderson
Thu Mar 7 23:22:06 EST 1996