I could not get the Lightspd cgi component to work properly until I enabled the auth module and set a username and password on the cgi-bin directory. BackupPC uses the REMOTE_USER env to check if you are logged in.

To set this up I uncommented the "mod_auth" line and added
<file>
auth.backend               = "plain"
auth.backend.plain.userfile = "/ffp/etc/lighttpd.user"

auth.require               = ( "/cgi-bin" =>
                               (
                                 "method"  => "basic",
                                 "realm"   => "BackupPC",
                                 "require" => "valid-user"
                               )
                             )
</file>

The lighttpd.user file is simply a USERNAME:PASSWORD style

Some good info at:

http://www.cyberciti.biz/tips/lighttpd-setup-a-password-protected-directory-directories.html

http://solstice.eplt.washington.edu/LighttpdConfig



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To use the web interface I needed to specify the backuppc username in the /ffp/etc/lighttpd.conf:

<file>
## change uid to <uid> (default: don't care)
server.username            = "backuppc"

## change uid to <uid> (default: don't care)
server.groupname           = "backuppc"
</file>

----
I installed and configured BackupPC as noted, including using the startup file.  I used the option to run BackupPC as user 'backuppc' based on the provided script.  After configuring a host and starting a backup, I was getting errors in the log file about no ping response.  As root I could ping the client.  However, as user backuppc I received the following error:

ping: permission denied (are you root?)

Non-root users cannot run ping in a standard busybox configuration.  Running the following command will let non root users run the ping successfully.

chmod 4755 ./busybox-netutils