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My custom monitoring program (probably not as advanced, it only does some light monitoring) accepts a text message back to shutdown the machine. Not perfect bu

by ErrantX 15y ago

My custom monitoring program (probably not as advanced, it only does some light monitoring) accepts a text message back to shutdown the machine. Not perfect but can work well as a line of defence.

markbao 15y ago
That's cool. How does it work? Is the text message just via email, and the server can accept an email back with a specific command?
- ErrantX 15y ago
  Servers are with Gandi - which has a hosting API. So... SMS gateway via some shared hosting I have had for ages. This calls a script which figures out which server I mean and uses the API to shut it down. I did used to use Twilio until they dropped international text messaging etc.
  - wrl 15y ago
    What are you using instead of Twilio now?
    - ErrantX 15y ago
      A shared hosting account which has a free (5 credits a month) SMS gateway included - I think it is reselling txtlocal.co.uk (who look quite good, but I haven't gotten round to trying them out directly yet). It was kinda thrown together in a few minutes after Twilio flaked :)
ma2rten 15y ago
I'm not an expert in this things, but can't sms messages be spoofed quite easily?
- ErrantX 15y ago
  I presumed they can be :) so my systems needs a text like this: <machine nickname> <passcode> It is on my todo list to improve this at some point - but not had chance yet.
  - ramidarigaz 15y ago
    I have a similar system, but instead of a plain passcode, I have a (simple, and probably not very secure) hashing method that I can do in my head. My message looks like this: <machine> <hashed passcode> <number> The passcode is "hashed" with the number. When the server receives the message, it adds the number to a deny-list. That way, the number is only good for one use. Also, the number has to conform to a certain pattern. I might change that to a pre-generated list of valid numbers, but for the moment, I can work out a valid number with pen and paper. Not perfect, but I think it's good enough.

by ErrantX 15y ago

My custom monitoring program (probably not as advanced, it only does some light monitoring) accepts a text message back to shutdown the machine. Not perfect but can work well as a line of defence.

markbao 15y ago

That's cool. How does it work? Is the text message just via email, and the server can accept an email back with a specific command?

ErrantX 15y ago
Servers are with Gandi - which has a hosting API. So... SMS gateway via some shared hosting I have had for ages. This calls a script which figures out which server I mean and uses the API to shut it down. I did used to use Twilio until they dropped international text messaging etc.
- wrl 15y ago
  What are you using instead of Twilio now?
  - ErrantX 15y ago
    A shared hosting account which has a free (5 credits a month) SMS gateway included - I think it is reselling txtlocal.co.uk (who look quite good, but I haven't gotten round to trying them out directly yet). It was kinda thrown together in a few minutes after Twilio flaked :)

ma2rten 15y ago

I'm not an expert in this things, but can't sms messages be spoofed quite easily?

ErrantX 15y ago
I presumed they can be :) so my systems needs a text like this: <machine nickname> <passcode> It is on my todo list to improve this at some point - but not had chance yet.
- ramidarigaz 15y ago
  I have a similar system, but instead of a plain passcode, I have a (simple, and probably not very secure) hashing method that I can do in my head. My message looks like this: <machine> <hashed passcode> <number> The passcode is "hashed" with the number. When the server receives the message, it adds the number to a deny-list. That way, the number is only good for one use. Also, the number has to conform to a certain pattern. I might change that to a pre-generated list of valid numbers, but for the moment, I can work out a valid number with pen and paper. Not perfect, but I think it's good enough.