Telephone tethering, Dynamic DNS and general fun

[Roger Oberholtzer]

We run openSUSE (11.2, and soon 12.1) in vehicles out on the road. They
are all over the place. Sometimes it would be nice to access these
systems from the comfort of the office. Especially when they are
thousands of kilometers away. So, I am exploring what options there are
for openSUSE. I think there are many. So perhaps I mean which option
combination is the best.

I think the basic connection will be from a telephone that supports
tethering. We expect that to be supplied by the local user. It would be
connected to the USB port of the openSUSE computer.

Once connected, openSUSE needs to get on the network. I would imagine
that a telephone that supports tethering handles the IP address assigned
to the computer? How it gets the address is of no concern. The computer
will get an address. Right?

Once it has the address, should it be possible, knowing the IP address,
to access the computer from the outside world? The whole discussion here
assumes that this is possible. Perhaps that is controlled by the
telephone? Or the local phone company?

If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service? This will be used rather seldom. Mainly in
times of difficulty or support. I could even consider a stupid solution
where the system copies a file to a known IP address that we could look
at.

After that, the rest must be the regular service configurations.

Anyone else been there done that?




Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int [phone]
Mobile: Int [phone]
***@ramboll.se
________________________________________

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden
www.rambollrst.se

[C]

Post by Roger Oberholtzer
I think the basic connection will be from a telephone that supports
tethering. We expect that to be supplied by the local user. It would be
connected to the USB port of the openSUSE computer.

I do something like this all the time while traveling. You don't need
to use USB cables... it's easier than that.

My basic setup is:
- An Android phone
- My openSUSE laptop or my Android Tablet (OS is irrelevant, it'll
work with Windows and OSX too))

Steps to do what you want.

Do the initial setup
- On the Android phone go to Settings > Wireless & Networks >
Portable WiFi hotspot settings and set up your SSID and Security the
same as you do for a typical WiFi router.

- On the Laptop/tablet, go to the usual place you go in your
preferred desktop manager to add a WiFi router, and set it up to
connect to the SSID you just defined... same as you do for any WiFi
router.

On the road/in the field
- On the Android phone, go to Settings > Wireless & Networks and
enable Portable WiFi hotspot
- If the laptop or tablet has been previously configured correctly it
will automatically find the activated WiFi hotspot and connect.

Post by Roger Oberholtzer
Once connected, openSUSE needs to get on the network. I would imagine
that a telephone that supports tethering handles the IP address assigned
to the computer? How it gets the address is of no concern. The computer
will get an address. Right?

Yes. This works the same as a WiFi router - the device is given a
local IP by the phone.

Post by Roger Oberholtzer
Once it has the address, should it be possible, knowing the IP address,
to access the computer from the outside world? The whole discussion here
assumes that this is possible. Perhaps that is controlled by the
telephone? Or the local phone company?
If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service? This will be used rather seldom. Mainly in
times of difficulty or support. I could even consider a stupid solution
where the system copies a file to a known IP address that we could look
at.

Run ddclient on the laptop... use DynDNS to manage the dynamically
assigned IP address from the phone company. After connecting, it
shouldn't take more than a couple of minutes for the device to be
remotely accessible via URL... you can ssh to the remote device etc
the same as if it was connected to a wired network.

This of course assumes that the phone company doesn't put limitations
on the phone contract in use... for me this all worked, and I can
connect to tethered devices.. there is no drama.

I tried this about 18 months ago with an iPhone and it was nothing but
trouble - that may have changed with the iOS updates... I don't know,
but on Android, it's very very simple and straight forward.

I would highly recommend of course that you test drive it yourself,
because your mobile provider is different than mine, and your config
is different etc etc.. Some providers get grumpy if you start
shuffling huge amounts of data, or have "unlimited" data for the first
2GB and then drop your access speeds to a crawl after you hit the cap.

It should be a real simple process using Android phones though.

C.

[Per Jessen]

Post by Roger Oberholtzer
We run openSUSE (11.2, and soon 12.1) in vehicles out on the road.
They are all over the place. Sometimes it would be nice to access
these systems from the comfort of the office. Especially when they are
thousands of kilometers away. So, I am exploring what options there
are for openSUSE. I think there are many. So perhaps I mean which
option combination is the best.
I think the basic connection will be from a telephone that supports
tethering. We expect that to be supplied by the local user. It would
be connected to the USB port of the openSUSE computer.
Once connected, openSUSE needs to get on the network. I would imagine
that a telephone that supports tethering handles the IP address
assigned to the computer? How it gets the address is of no concern.
The computer will get an address. Right?

I would expect so, yes.

Post by Roger Oberholtzer
If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service? This will be used rather seldom.

You wouldn't necessarily need DNS, your mobile unit could just open a
connection to e.g. your web-browser, and you'd know the client id.

Post by Roger Oberholtzer
Mainly in times of difficulty or support. I could even consider a
stupid solution where the system copies a file to a known IP address
that we could look at.
After that, the rest must be the regular service configurations.
Anyone else been there done that?

Last year I did have a look around for phones that would support
tethering, but I ended up buying a USB GSM modem instead.

[Lars Müller]

On Thu, Dec 08, 2011 at 04:32:31PM +0100, Roger Oberholtzer wrote:
[ 8< ]

Post by Roger Oberholtzer
Once connected, openSUSE needs to get on the network. I would imagine
that a telephone that supports tethering handles the IP address assigned
to the computer? How it gets the address is of no concern. The computer
will get an address. Right?
Once it has the address, should it be possible, knowing the IP address,
to access the computer from the outside world? The whole discussion here
assumes that this is possible. Perhaps that is controlled by the
telephone? Or the local phone company?

Most mobile network providers use address spaces from the ranges as
defined in RFC 1918.

Post by Roger Oberholtzer
If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service?

And then the name of your mobile host gets resolved for example to
10.10.4.6 and you wonder why you can't reach it.

Use openvpn and to make the certificate handling easy use the YaST CA
management tool.

Post by Roger Oberholtzer
This will be used rather seldom. Mainly in
times of difficulty or support. I could even consider a stupid solution
where the system copies a file to a known IP address that we could look
at.

Instead of wasting your time with such a homegrown and very likely non
working approach I would use openvpn.

Lars

[James Knott]

Post by Roger Oberholtzer
We run openSUSE (11.2, and soon 12.1) in vehicles out on the road. They
are all over the place. Sometimes it would be nice to access these
systems from the comfort of the office. Especially when they are
thousands of kilometers away. So, I am exploring what options there are
for openSUSE. I think there are many. So perhaps I mean which option
combination is the best.
I think the basic connection will be from a telephone that supports
tethering. We expect that to be supplied by the local user. It would be
connected to the USB port of the openSUSE computer.

Tethering works, but you might also want to consider those "stick"
devices for wireless access. They appear to the computer as a dial up
modem and they do work with Linux too.

Post by Roger Oberholtzer
Once connected, openSUSE needs to get on the network. I would imagine
that a telephone that supports tethering handles the IP address assigned
to the computer? How it gets the address is of no concern. The computer
will get an address. Right?
Once it has the address, should it be possible, knowing the IP address,
to access the computer from the outside world? The whole discussion here
assumes that this is possible. Perhaps that is controlled by the
telephone? Or the local phone company?
If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service? This will be used rather seldom. Mainly in
times of difficulty or support. I could even consider a stupid solution
where the system copies a file to a known IP address that we could look
at.

With tethering, you'll likely find you have a NAT address, which means
you will not be able to reach the remote computers. Even if the phone
gets a public address, it still uses NAT for tethered devices. One way
around this is to use 6in4 tunnelling to use IPv6 on the remote
computers. You may also have to use it in the office, if you don't
otherwise have IPv6 available. I use the client from
http://gogonet.gogo6.com. If you register your connection, you will get
a static IPv6 address. The Linux client has to be compiled, but there
is an issue with 12.1. However, I have a fix available for that.

I use that gogo6 client to set up my own /56 subnet (that's about a
trillion times the entire IPv4 address space) and run it in single
address mode on my notebook. It works well.

[Roger Oberholtzer]

Post by Per Jessen
You wouldn't necessarily need DNS, your mobile unit could just open a
connection to e.g. your web-browser, and you'd know the client id.

Indeed some simple mechanism could let us obtain the IP address. Maybe
DynDNS is overkill.

Post by Per Jessen

Post by Roger Oberholtzer
Mainly in times of difficulty or support. I could even consider a
stupid solution where the system copies a file to a known IP address
that we could look at.
After that, the rest must be the regular service configurations.
Anyone else been there done that?

Last year I did have a look around for phones that would support
tethering, but I ended up buying a USB GSM modem instead.

We would need a system that works everywhere. We were thinkig a user
would use their own phone as they have all the local phone company
details sorted out. Of course they would have to have a connection that
allows this sort of thing.
--
Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int [phone]
Mobile: Int [phone]
***@ramboll.se
________________________________________

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden
www.rambollrst.se

[Roger Oberholtzer]

Post by C

Post by Roger Oberholtzer
I think the basic connection will be from a telephone that supports
tethering. We expect that to be supplied by the local user. It would be
connected to the USB port of the openSUSE computer.

I do something like this all the time while traveling. You don't need
to use USB cables... it's easier than that.

Not a laptop. They are rack mounted computers. They have USB so that it
perhaps easiest. Unless different phones are different. Then maybe a USB
wireless dongle that we supply would make things easier.
--
Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int [phone]
Mobile: Int [phone]
***@ramboll.se
________________________________________

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden
www.rambollrst.se

[Roger Oberholtzer]

Post by Lars Müller

Post by Roger Oberholtzer
If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service?

And then the name of your mobile host gets resolved for example to
10.10.4.6 and you wonder why you can't reach it.
Use openvpn and to make the certificate handling easy use the YaST CA
management tool.

Post by Roger Oberholtzer
This will be used rather seldom. Mainly in
times of difficulty or support. I could even consider a stupid solution
where the system copies a file to a known IP address that we could look
at.

Instead of wasting your time with such a homegrown and very likely non
working approach I would use openvpn.

OK. Here could be my chance to finally play with that. But wouldn't the
10.10.x.x. address be a problem anyway?
--
Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int [phone]
Mobile: Int [phone]
***@ramboll.se
________________________________________

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden
www.rambollrst.se

[Roger Oberholtzer]

Post by James Knott
Tethering works, but you might also want to consider those "stick"
devices for wireless access. They appear to the computer as a dial up
modem and they do work with Linux too.

I have had mixed luck with them. The most common one in Sweden (A Huwei
from Tele2) almost works with Linux. There are endless discussions about
it. I even had one on this list a year or so ago. But at the end of the
day it does not work.

I understand that Vodaphone have a modem that has Linux support. I think
they actively support it. If I could get one, I guess I could use any
GSM card in it? The customer could either have a dedicated GSM card, or
a pay-as-you-go card they buy locally?

We do not really want to get in the position of supporting exotic local
devices. We are hoping for hardware we can select and deliver that works
everywhere.

Post by James Knott

Post by Roger Oberholtzer
Once connected, openSUSE needs to get on the network. I would imagine
that a telephone that supports tethering handles the IP address assigned
to the computer? How it gets the address is of no concern. The computer
will get an address. Right?
Once it has the address, should it be possible, knowing the IP address,
to access the computer from the outside world? The whole discussion here
assumes that this is possible. Perhaps that is controlled by the
telephone? Or the local phone company?
If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service? This will be used rather seldom. Mainly in
times of difficulty or support. I could even consider a stupid solution
where the system copies a file to a known IP address that we could look
at.

With tethering, you'll likely find you have a NAT address, which means
you will not be able to reach the remote computers. Even if the phone
gets a public address, it still uses NAT for tethered devices. One way
around this is to use 6in4 tunnelling to use IPv6 on the remote
computers. You may also have to use it in the office, if you don't
otherwise have IPv6 available. I use the client from
http://gogonet.gogo6.com. If you register your connection, you will get
a static IPv6 address. The Linux client has to be compiled, but there
is an issue with 12.1. However, I have a fix available for that.
I use that gogo6 client to set up my own /56 subnet (that's about a
trillion times the entire IPv4 address space) and run it in single
address mode on my notebook. It works well.

I was expecting a NAT solution was going to be used. But since the
computer knows where we are, perhaps a vpn, as has been suggested in
another post in this thread, between us?
--
Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int [phone]
Mobile: Int [phone]
***@ramboll.se
________________________________________

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden
www.rambollrst.se

[James Knott]

Post by Roger Oberholtzer
I was expecting a NAT solution was going to be used. But since the
computer knows where we are, perhaps a vpn, as has been suggested in
another post in this thread, between us?

VPNs work well. I have used openVPN for years, but IPSec is becoming
more popular lately.

[C]

Post by Roger Oberholtzer
I understand that Vodaphone have a modem that has Linux support. I think
they actively support it. If I could get one, I guess I could use any
GSM card in it? The customer could either have a dedicated GSM card, or
a pay-as-you-go card they buy locally?
We do not really want to get in the position of supporting exotic local
devices. We are hoping for hardware we can select and deliver that works
everywhere.

I've got one of those too :-) I have too many ways to get connected
to the internet :-P

The Vodafone guys were developing their own custom software for the
modems they make. Take a look here:
https://forge.betavine.net/projects/vodafonemobilec/
There hasn't been much work on it for a while now... I haven't tested
to see of it works in openSUSE12.1 - you might get away with using the
NetworkManager...


C.

[Lars Müller]

Post by Roger Oberholtzer

Post by Lars Müller

Post by Roger Oberholtzer
If the IP address could be accessed, I guess the next step might be to
register it with a dynamic DNS service so it can be know to us. Any
suggestions on a DNS service?

And then the name of your mobile host gets resolved for example to
10.10.4.6 and you wonder why you can't reach it.
Use openvpn and to make the certificate handling easy use the YaST CA
management tool.

Post by Roger Oberholtzer
This will be used rather seldom. Mainly in
times of difficulty or support. I could even consider a stupid solution
where the system copies a file to a known IP address that we could look
at.

Instead of wasting your time with such a homegrown and very likely non
working approach I would use openvpn.

OK. Here could be my chance to finally play with that. But wouldn't the
10.10.x.x. address be a problem anyway?

No. I see this with different mobile network operators. Looks like
IPv4 addresses finally get handled a bit more strict. This might also
be required by the roaming nature of the connection or other technical
reasons.

Here as an example the settings I got while I verified that I'm not
telling you a fairytale.

A call to "ip r s" shows:
default via 10.64.64.64 dev ppp0 proto static
10.64.64.64 dev ppp0 proto kernel scope link src 10.57.75.50

With "ip a s ppp0" brings:
5: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc
pfifo_fast state UNKNOWN qlen 3
link/ppp
inet 10.57.75.50 peer 10.64.64.64/32 scope global ppp0

If you then have to access a 10.0.0.0/8 network at the other end of the
connection via your openvpn tunnel there are two addresses which can't
be reached. 10.64.64.64 and 10.57.75.50 in this example.

If you use a smart phone to handle the connection you might even get an
additional private network involved between the machine you try to
connect and the phone. But the setting of this WiFi network you have
under your full control.

Lars

[Per Jessen]

Post by Roger Oberholtzer

Post by C

Post by Roger Oberholtzer
I think the basic connection will be from a telephone that supports
tethering. We expect that to be supplied by the local user. It
would be connected to the USB port of the openSUSE computer.

I do something like this all the time while traveling. You don't
need to use USB cables... it's easier than that.

Not a laptop. They are rack mounted computers. They have USB so that
it perhaps easiest. Unless different phones are different. Then maybe
a USB wireless dongle that we supply would make things easier.

Without knowing your environment, that sounds to me like the option most
likely to succeed. When the operator plugs in the USB modem, have your
system auto-dial to a preset number and voila!

[Per Jessen]

Post by Roger Oberholtzer

Post by James Knott
Tethering works, but you might also want to consider those "stick"
devices for wireless access. They appear to the computer as a dial
up modem and they do work with Linux too.

I have had mixed luck with them. The most common one in Sweden (A
Huwei from Tele2) almost works with Linux. There are endless
discussions about it. I even had one on this list a year or so ago.
But at the end of the day it does not work.

When I bought my USB GSM stick almost two years ago, I ignored all the
Telco "deals" and just went for an "iCON 505M" by Option:

https://www.distrelec.ch/icon-505m-umts-usb-stick/option/gi1505-11563/847919/it-&-zubeh%C3%B6r

I have not yet bothered with getting it to work with Network Manager, I
just plug it in, run a script, then use minicom for sending AT commands
to dial up.

[Per Jessen]

Post by Per Jessen

Post by Roger Oberholtzer

Post by C

Post by Roger Oberholtzer
I think the basic connection will be from a telephone that
supports tethering. We expect that to be supplied by the local
user. It would be connected to the USB port of the openSUSE
computer.

I do something like this all the time while traveling. You don't
need to use USB cables... it's easier than that.

Not a laptop. They are rack mounted computers. They have USB so that
it perhaps easiest. Unless different phones are different. Then maybe
a USB wireless dongle that we supply would make things easier.

Without knowing your environment, that sounds to me like the option
most likely to succeed. When the operator plugs in the USB modem,
have your system auto-dial to a preset number and voila!

Actually:

... have your system auto-dial and voila! Then acquire the IP-address by
automatically sending an email or visiting a dedicated website or some
such. Depends on how automatic you need this stuff to work - if you're
trying to assist a local engineer, he might be able to just tell you
what the IP is :-)

[Roger Oberholtzer]

Post by Per Jessen
... have your system auto-dial and voila! Then acquire the IP-address by
automatically sending an email or visiting a dedicated website or some
such. Depends on how automatic you need this stuff to work - if you're
trying to assist a local engineer, he might be able to just tell you
what the IP is :-)

That is the situation. I would think that information could be reported.
Even a simple command run. But if something needs to be configured in
the openSUSE machine, that could be problematic. We are already near
heretics in that we subject our customers to Linux - even if mainly in
the comfort of KDE. Gasp! But if we start asking to have something
configured, well, heads might very well roll :)



Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int [phone]
Mobile: Int [phone]
***@ramboll.se
________________________________________

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden
www.rambollrst.se