wimpunk:
> If you want to check on malicious links, postfix could verify if the
> link it points to is a file with the correct features.

The .forward file is a "program" that can execute arbitrary shell
commands and that can write to arbitrary files, with the privileges
of the recipient (which may be "root").  All this makes .forward a
sensitive file.

Common-sense measures to protect a sensitive file are:

- Keeping the file within a directory that is writable only by the
  recipient or by the system adminstrator.

- Using a "hidden" name in the user's home directory, such that the
  file isn't easily destroyed by mistake.

If you want Postfix to look for .forward files in other locations,
then you can edit the forward_path parameter setting. The default
is to look under the home directory.

    forward_path = $home/.forward${recipient_delimiter}${extension}, 
        $home/.forward

Here is an example with per-user files under /var/forward:

    forward_path = /var/forward/$user

Of course you can mix the two models.

        Wietse

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