Firewalls in general use the information they have about a packet to decide whether to pass it on or not (a bit of a simplification, but acceptable for immediate purposes). A junk phone call, befor you answer it, gives very little information out about itself ... if you have Caller ID, it *might* tell you the source phone number (though telemarketers will often block this information). But aside from that, it tells you nothing about whether the call is from your beloved aunt or from someone with a once-in-a-lifetime chance to buy into a timeshare at LOW, LOW PRICES.
So ... before we wonder about implementation details, the core question to ask is what any abstract device would screen on? If the Caller ID info ... well, there's a pretty mature line of Caller-ID devices now, and I doubt a Linux-based addition to the mix would be attractive (mostly because it would require specialized hardware to process the Caller-ID info ... I doubt a stock "real" modem can receive and decode it).
I'd think you would find more relevant expertise on lists connected to Linux-based voice-answering-machines, using software like vgetty. They would certainly know more about voice-capable modems than most of us here do. You might want to explore that and other possibilities rahter then starting here at LEAF.
Good luck.
At 08:29 PM 3/7/2003 -0600, [EMAIL PROTECTED] wrote:
As I understand it, a firewall prevents computers from communicating undesirable communications. Poorly worded, perhaps, but I am sure it addresses the intent of firewalls.
I get lots of undesireable communications on my telephone. There seems to be a marketing industry devoted to using my phone number as a sales tool. I am sure everyone on the reflector can identify with this plague. Telephone ettiquite prevents hanging up on calls regardless of intent, but it should also prevent calls of this nature. No one, with the possible exeption of telemarketers, has rude intentions. So we listen patiently to the rude people who have disrupted our privacy and tell them 'no' as politely as we can.
Getting to the point, has anyone every considered building a firewall to prevent this abuse? A telephone firewall. Could something of this nature be implemented on an LRP box? A rethorical question because I know it can be implemented. I would do that but don't know how. My lack of knowledge extends to the programming. I am pretty sure I can handle the hardware requirements.
The question is, does anyone know of any efforts to do this?
Better yet, does anyone know of any software that does this? It would be a plus if the software was open source and targeted to a linux system.
My Dachstein firewall is on all the time, connected to my cable modem. It could just as well be handling telephone traffic on the same 24/7/365 basis.
Positive comments are encouraged. Please don't flame me for my other than TCP/IP interest.
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