Mailinglist Archive: opensuse (769 mails)

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Re: [opensuse] VoIP ATA does NOT need to have a foxed address, only the ISP does
On 05/27/2016 12:07 AM, Andrei Borzenkov wrote:
27.05.2016 04:46, James Knott пишет:
On 05/26/2016 04:50 PM, Anton Aylward wrote:
Actually, with NAT, you have to use an STUN server to
communicate the
real address to the other end. Otherwise, it would try to
use the NAT address, which wouldn't be reachable. This is
just one example of a hack made necessary by NAT.
I'm sorry, no you don't need a STUN server.

Perhaps some servile providers configure their systems so to make
it necessary, but mine certainly doesn't!

In fact they insist that a STUN is NOT to be configured.


OK, your VoIP phone is behind NAT, with an RFC 1918 address. The
other end has to be able to reach your phone. What address does it
use? And how does it get it?

Linksys ATA is using SIP NAT traversal. So yes, in this case
separate STUN server is not needed. Which does not mean of course
that two VoIP communicate directly without any help.


Thank you Andrei.

I've tried persuading many of my friends&relations to use VoIP but to be
honest, the only people who seem the least bit interested in talking to
me on the phone are my doctor/dentist calling to confirm/remind
appointments and headhunters who insist on phone interviews, which I
consider as lame and useless as email interviews, after all so much of
meaningful communication is face to face, non-verbal..

That constraint means they dial me using the pre-WW2 style UI that they
are familiar with. In "Dead men don't wear plaid" Rachel Ward adapted
Lauren Bacall's great line from "To have and have not":

Juliet Forrest: If you need me, just call. You know how to dial,
don't you? You just put your finger in the hole and make tiny little
circles.

It was all in the way she said it ....

Direct communication ... well teh bg problem with telephone is that it
demands the presence of both parties, its 'synchronous' whereas email
and texting is asynchronous. Which is even more wonderful, as this list
demonstrates, when you are in different time zones.

One of the of-quoted put-down of the phone:

"This 'telephone' has too many shortcomings to be seriously
considered as a means of communication. The device is inherently of
no value to us." Western Union internal memo, 1876

came about because of just that; telegrams were delivered, you had hard
copy; you didn't have to respond in real time ....

Right now it turns out I don't use the phone much, just a few people who
haven't caught up on late 20th century technology, haven't got a
computer like my aged stepmother. She'll never get IPv6; she hasn't
even got IPv4.

To be absolutely honest, I have misgivings about VoIP. Some of teh
head-hunters who call are almost unintelligible. I suspect that the
'open standard' of VoIP is a bit like some of the IPv4 was back in the
1980s. I recall going to InterOp in SF a few times and being at
"interoperability bake-off" there where the various vendors tried
verifying they could all communicate with one another. Quite a few
fails. And Cisco refused point blank to participate. A company I
worked for didn't have Cisco equipment and one of its peers did and when
the leased line went down they couldn't bring it back up; Cisco's
PTP/PAP was not conformant/interoperable (at that time) and the
netadmins had to phone each other up (long distance) and do various
negations and stuff to make it work. I was later told that Cisco bout
out NetBalazer and ended up using their technology.

I suspect that we're going through a similar cycle with VoIP; various
implementations are conforming to the standard as written, but that
doesn't mean that they interoperate smoothly.

Heck, just about everyone here has enough experience in 'software
doesn't always work the way it say its supposed to, every time, even
after patching...' to accept that even corporate & governmental stuff
can't be relied on.


--
A: Yes.
> Q: Are you sure?
>> A: Because it reverses the logical flow of conversation.
>>> Q: Why is top posting frowned upon?

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