I am not a security expert by any means, but port knocking came to mind. You
may find this wiki page interesting:
--- Rob Conway <rjconway@...
> I have my UNSLung 6.8 SLUG monitoring my fish tank and I now want to move
> onto controlling various devices. I have investigated cgi scripts which work
> OK however worried about security. My SLUG will provide an output contact
> (via 1wire) which will be sent into a PIC processor which provides the
> real-time controls. I was thinking to get the PIC to monitor a series of
> contact pulses from the SLUG before turning anything on or off.
> Is it posible to setup a mail server/client on the slug and if I email the
> slug a specifc (ie exact) phrase in the subject line it will go off and start
> a script. Or is their another secure way. I am also very concerned with not
> loading my slug up too much as it has alot of trend analysis to do at various
> times together with its web server thhtp.
> best regards