Книга: Linux Network Administrator Guide, Second Edition

Forwarding

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:

####################
# pablo
system          pablo
...
forward         uchile
####################
# uchile
system          uchile
...
forward-to      pablo

The forward-to entry for uchile is necessary so that any files returned by it are actually passed on to pablo. Otherwise UUCP would drop them. This entry uses a variation of the forward command that permits uchile to send files only to pablo through seci, not the other way round.

To permit forwarding to any system, use the special keyword ANY (capital letters required).

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