On 27/12/2020 16:07, Chris Green wrote:
> The Natural Philosopher  wrote:
>>>> Start with the assumption that you cant open a connection to a mobile
>>>> equpped pi, but 'always on' FROM the pi  wont be costly.
>>>>
>>> So, if one has 'always on' FROM the pi does that then just require
>>> some sort of dynamic dns service to be able to ssh *to* it?
>>>
>> No, not even that will work.
>>
>> Because that will take you to the ISPS NAT router and there will be no
>> way to route onward to the Pi.
>>
>> *Only if the Pi initiates the connection* will the NAT router set up a
>> mapping between public IP/port and PI IP/port.
>>
>> Its analogous to your current wifi setup.  The Pi will have to be online
>> and permanently connected in some way to a publiclly accessible server
>> that you can use as a gateway.
>>
> OK, my current WiFi set up is (as a mobile connection would be) behind
> a NAT router and I set up reverse ssh tunnels to allow me to connect
> 'on demand' to the Pi (BBB).  So I can do exactly the same using the
> mobile data connection.
>
> Will the mobile provider object to the connection being up all the
> time but with virtually no data going through it?
>
That is what any smart phone in your pocket does. Why should it? In
reality all that is going on is keepalive packets going to the cell
tower and probably keepalive packets keeping alive any TCP connection
you have




--
"In our post-modern world, climate science is not powerful because it is
true: it is true because it is powerful."

Lucas Bergkamp

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