commands rmail rnews bsmtp File Transfers Taylor UUCP (Web hosting company)
commands rmail rnews bsmtp 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 to either 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 upload and download files. In addition, you can configure the directories that files may be copied to and from. 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 are 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.100 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 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 exam ple: system pablo … local-send /home ~ local-receive /home ~/receive remote-send ~ !~/incoming !~/receive remote-receive ~/incoming 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 from 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 files to incoming. A major problem with file transfers using UUCP is that it receives files only to directories that are world- writable. This may tempt some users to set up traps for other users. However, there’s no way to escape this problem outside of disabling UUCP file transfers altogether. Forwarding UUCP provides a mechanism to have other systems execute file transfers on your behalf. For instance, suppose your system has uucp access to a system called seci, but not to another system called uchile. This allows you to make seci retrieve a file from uchile for you and send it to your system. The following command would achieve this: $ uucp -r seci!uchile!~/find-ls.gz ~/uchile.files.gz This technique of passing a job through several systems is called forwarding. On your own UUCP system, you would want to limit the forwarding service to a few hosts you trust not to run up a horrendous phone bill by making you download the latest X11R6 source release for them. By default, Taylor UUCP prohibits forwarding altogether. To enable forwarding for a particular system, you can use the forward command. This command specifies a list of sites the system may request you to forward jobs to and from. For instance, the UUCP administrator of seci would have to add the following lines to the sys file to allow pablo to request files from uchile: #################### You may use a tilde (~) character to refer to the UUCP public directory, but only in UUCP configuration files; outside it usually translates to the user’s home directory.