Mailinglist Archive: opensuse (770 mails)

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Re: [opensuse] connecting my telephone to the internet
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On 2012-08-25 04:07, James Knott wrote:
Carlos E. R. wrote:
On the other hand, do you remember those movies where the bad guy makes a
phone call to
the police and the call has to last less than 20" or he is identified?
That's rubbish,
you are identified on on the first second, while ringing, at least on
countries like
Spain.

Actually, it didn't used to be rubbish. I have worked in telecom going back
40 years and
at one point early in my career, I actually worked on some of the old step by
step relay
systems and even learned to trace calls through them. There's no way it
could be done in
only 20 seconds. Modern, SS7 sytstems are of course quite different. Also,
the phone ID
can be spoofed. I get plenty of telemarketing calls where that is done. The
originating
switch or PBX is the one that provides the ID and it can be set to anything.
For example,
according to my phone's log, I received a call on Aug 10 from 10000000000.
That is in no
way a valid number, yet it managed to reach my phone. This is via a regular
phone company
that provides my home phone. Also, a few years ago, I worked on a phone
system where the
customer insisted there be no caller ID on outgoing calls, as it was for a
woman's shelter
and they didn't want anyway for someone to track where those women were. I
have also set
up VoIP PBXs, where someone in one location could call through another
location and appear
as though they originated at that 2nd location. It's not at all difficult to
do with
today's equipment, so accepting from the phone company is not quite as secure
as you
think.

I also have worked on that field, but not that long. My experience is with the
5EEE only. It
is precisely due to that work that I became interested in Linux ;-)

Legislation in Spain is such that law insists calls are identified because it
is needed to
know whom to charge the phone call to, across different companies. It started
when the
government forced the only telco in existence here (Telefónica), in 1997, to
accept indirect
phone calls routed via another company (you prefix your call with a 3 digit
number, and the
call is routed via another telco for the long distance part).

I too have seen those strange numbers, like 000000, in my terminal, but
unfortunately, after
I stopped working there, so I don't have inside knowledge on them. I believe
they come via
internet gateways.

I know that with VoIP machines you have a lot of liberty, you can do anything
with numbers
and names and routings. It is up to you what you do or fake, which also kind of
scares me.

Of course, the typical is having a company with two or more sites, and routing
the call,
inside your network, to the POT network from the site closest to the
destination, so that the
call is charged local charges instead of long distance.

- --
Cheers / Saludos,

Carlos E. R.
(from 12.1 x86_64 "Asparagus" at Telcontar)
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