iBeacon

24 07 2014

Aeronautical beacons are well-known but the only relation to my topic is that the communication between Apple’s iBeacons and mobile devices also works over the air but not in the visible frequency spectrum of electromagnetic waves but in the invisible near frequency spectrum.

About waves …

Your iOS devices are nothing without waves.
Waves are the food for every mobile device connected to the internet, your carrier, or an iBeacon and contain the information e.g. needed for your browser to show websites, for a phone call to transmit your voice, and for an iBeacon connection to exchange data if you are near to it.

You all know water waves, seismic waves and waves that transmit the sound from one person to another or from speakers to your ear. Sometimes sound waves contain good news or bad news. Whatever is transmitted by waves it’s always INFORMATION.

In case of iPhones contacting your carrier or iPads contacting your wireless access point, waves are Electromagnetic Waves. In contrast to water waves (propagating through water), the sound (propagating through gas) and seismic waves (propagating through the earth) electromagnetic waves don’t need a medium. They also can carry information while propagating through the vacuum with the speed of light (about 300.000 m/sec). That’s pretty fast and helps when transmitting information to your device because there are many disturbers around us and so information has to be transmitted several times before being identified as those destined for you.

Look here for waves in motion

Simple Wikipedia

Properties of waves are among others the amplitude (height of cycles) and the frequency (number of cycles per second). Sound waves have a low frequency when we hear a deep tone. The frequency is measured in Hertz (Hz).

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Image (1) shows an AM (amplitude modulated) wave and Image (2) an FM (frequency modulated) wave. You all know AM and FM if you ever looked on a radio’s dashboard. The more important method is to transmit information with a frequency modulated wave.

In an area of interference signals may be extinguished due to the fact that a wave peak may meet a wave trough.

About iBeacons …

iBeacon is Apple’s name for a technology that allows mobile apps to know how close they are to tiny, low-cost, wireless transmitters called hardware iBeacons.
iBeacons technology isn’t a development of Apple’s. Many recent Android devices already support it. iBeacons broadcast signals using the well-known Bluetooth Low Energy (BLE) standard, allowing precise, indoor geo-location (often called ‘Micro- location’) where smartphones or tablets are not able to receive GPS signals from satellites, but also contextual interaction and engagement, as proximity to an iBeacon can trigger some specific app functionalities or even launch an app.

Bluetooth low energy, Bluetooth LE, or BLE, marketed as Bluetooth Smart, is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group aimed at novel applications in the healthcare, fitness, security, and home entertainment industries. Compared to “Classic” Bluetooth, BLE is intended to provide considerably reduced power consumption and cost while maintaining a similar communication range.
Bluetooth LE was originally introduced under the name Wibree by Nokia in 2006. It was merged into the main Bluetooth standard in 2010 with the adoption of the Bluetooth Core Specification Version 4.0.
Mobile operating systems including iOS, Android, Windows Phone and BlackBerry, as well as OS X and Windows 8, natively support Bluetooth low energy. The Bluetooth SIG predicts more than 90 percent of Bluetooth-enabled smartphones will support the low energy standard by 2018.

iBeacon-enabled apps are notified when the device moves in and out of the range of iBeacons. They monitor the distance as their proximity changes over time. This allows apps to know precisely where they are not in terms of a map but relative to known points within a building.

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iBeacons are tiny battery-operated radio signal stations you can place wherever you want; if your Mobile device gets within range, it senses iBeacons and locates itself.
iBeacons broadcast a “I am here!” message (approximately once per second) to any device within range of the Bluetooth Low Energy radio signal; since each iBeacon has its own ID, the Mobile device can tell them apart and recognize the context of the world around itself.
iBeacons usually just identify themselves by an ID but do not transfer other data than this.

Micro-locating a device can initiate interaction, engagement, and contextual information. Mobile apps receiving signals of iBeacons can be triggered triggered to perform a specific action on a specific mobile device at a specific time and in a specific location.

Summarized, iBeacon signals can

  • precisely locate you within a building
  • triangulate constantly and quietly in the background
    When you pull out your phone, the right content is there waiting for you. This immediacy is one big advantage Bluetooth now has over clunky predecessors like NFC and QR codes.
  • make suggestions what you can do with the help of an iBeacon capable app

iBeacons therefore make it possible to seamlessly engage with people in a physical space through their mobile devices.

Some examples …

Contextualized deals
iBeacons technology allows to convey specific, customized deals to shoppers based on time and day, their purchase history, their loyalty, etc. Think of very customized offers; for example a shopper has checked an item in a store but did not purchase it. The retailer then can offer the shopper a discount via email or directly on the mobile device the next time he enters the same store (or an other chain store).

Monitoring shoppers behavior
Monitoring shoppers behavior (store visits, walking-paths, etc.) is another possibility. With the help of an iBeacons the retailer may get the information (in real-time) that the shopper has been standing in front of one specific display for more than three minutes; sensing second-by-second a shopper’s (inferred) interest about a specific product, the system can supply additional information such as online reviews and – talking about fashion – other available styles or colours. As you go on shopping, a blue tie might (metaphorically) tell you: “I’m perfect with the gray suit you purchased here last week”.

This is one side of a coin and this application of iBeacons might be nerve-racking for many of us who already suffer from the constant onslaught of ad on TV, on websites, and nearly all other areas of live.

So let’s have a look on the coin’s backside.

In developed countries with public health care the emphasis on personal responsibility has been the best way to both reduce costs and make the system more efficient. In America you have to go through the gauntlet of health care providers and insurance providers and pharmaceutical companies to take charge of your own good health. If Apple’s iBeacon software is installed in the next ambulance to arrive at my home then an iPhone might light up with your emergency information automatically once you are inside the vehicle. You might not even be conscious. But your iPhone can give them what they need to know to start treating you. The device might also tell them you have had high blood pressure for the past six weeks and rising. All this with a personal tracking iWatch and the M7 motion processor on the iPhone.

To emphasize the more useful applications of the iBeacon technology let me another example.

You are walking through a museum of art, iBeacon micro-locates you and provides information about the artist of an artwork you are looking at.

It would be no problem to write further 10 blogs about possible applications of this technology. It’s up to the creativity to find out nearly unlimited further applications.

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Feel free to download this map from my Box account.

The alternative file formats have been created with iThoughts HD for iPad (.ITMZ file format). Compatibility to other tools is limited. The DOCX file format is suggested for those who don’t use a mind mapping tool. The file contains the image as well as a detailed outline of all topics.

Application File format
Adobe Reader PDF
Apple iWork/Microsoft Office DOCX
iThoughts ITMZ
MindManager MMAP
XMind XMIND

The crux is that a new operating system provides an option – like for Location Services – to turn off the bit radiation which might affect our health. The two communicating devices, the iBeacon and the iPhone – shouldn’t get control over our most important processor, our brain.

Platforms …

The great news about iBeacons technology is that both Apple (with iOS and OS X) and Google (with Android) have committed to support for Bluetooth LE – this means very, very broad availability (literally millions of devices are already iBeacon-enabled) and there is no danger of launching services targeted at a single operating system.

What about Microsoft?

Microsoft appears to have recently added support for Bluetooth Low Energy in Windows 8 and Windows Phone 8; Nokia’s recent Lumia WP8 phones are confirmed to include BLE hardware.

Some technical details …

An iBeacon identifies itself using three customizable values

  • Proximity UUID (128 Bit)
  • Major (16 Bit)
  • Minor (16 Bit)

So there are three levels to identify a micro-location: only Proximity UUID, Proximity UUID and Major, Proximity UUID and Major and Minor.

For example

  • Proximity UUID identifies your entire retail company, Major identifies a specific store and Minor specify individual shelves or different checkout tills inside each store.
  • Proximity UUID identifies your museum, Major identifies a specific gallery within the museum and Minor identifies an exhibit within that gallery.

The radio signals of iBeacons allow to calculate distances in qualitative

  • Immediate
    (less than 50 cm)
  • Near
    (approximately 50 cm to 2-5 m)
  • Far
    (more or less between 50 cm and 30-50 m, depending on walls, the iBeacon output power, and many other factors like interference)

Bluetooth low energy is not backward-compatible with the previous, often called Classic, Bluetooth protocol. The Bluetooth 4.0 specification permits devices to implement either or both of the LE and Classic systems. Those that implement both are known as Bluetooth 4.0 dual-mode devices.

Bluetooth LE uses the same 2.4 GHz radio frequencies as Classic Bluetooth, which allows dual-mode devices to share a single radio antenna. LE does, however, use a simpler modulation system.

iBeacon vs NFC vs QR-Codes …

I think we must not talk about QR-Codes which are powerful for industrial production but not accepted as a relevant source of information by the majority of people. Admittedly we might find QR-Codes on boxes containing iBeacons or NFC Tags.

Since Apple’s 2013 announcement, the press has been praising iBeacon for its ability to passively identify the in-venue presence of smartphone-equipped consumers. They have also been praising it for its ability to passively notify and then subsequently deliver localized information. These features, along with the press’ embrace of iBeacon’s perceived ease-of-use, location services, energy efficiency, security and low cost, have made iBeacon the sweetheart of the tech industry.

Since the press’ enthusiasm for iBeacon has gone largely unchallenged, many have taken the liberty to label NFC as irrelevant because it lacks iBeacon-like features. But, is this the truth?

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Although the NFC environment is very different and has many non-overlapping applications, it is still compared with iBeacons.

  • NFC range is up to 20 cm (7.87 inches) but the optimal range is < 4 cm (1.57 inches). iBeacons have a significantly larger range.
  • NFC can be either passive or active. When using passive mode, the power is sent from the reader device as radio signals. Whereas although Passif (a company acquired by Apple) has worked on reducing the energy consumption, a battery pack is still needed inside iBeacon tags at this time.
  • Most smartphones ship with both Bluetooth 4.0 LE and NFC support but at this time, no iOS device has been released with NFC support.
  • A BLE beacon is great for passively enabling a retailer’s mobile app to deliver promotions, coupons or offers direct to the consumer’s smartphone when the consumer is in the general vicinity. NFC can’t do that. But if you want to research a specific Nikon SLR, for example, you can scan an NFC-enabled shelf tag next to it and study to your heart’s content. BLE can’t deliver that much location granularity.

So the final conclusion is:

iBeacon is the much more powerful technique mainly because of it’s range and automated communication.

Advocates of the NFC technology might argue with the lower costs of NFC tags (about 0.5$) compared to iBeacons (about 25$). But because of the limited range you need far more NFC tags distributed e.g. in a retail store (approximate price Apr 2014).

iBeacon demo …

Here is a video showing iBeacons in action.
It was published on December 10, 2013 by InnoQuant, an advanced analytics software company founded in Barcelona in 2010. InnoQuant provides data analytics services and software solutions to solve problems of Big Data Analytics such as real-time mobile marketing.
InnoQuant technology allows users to monitor, analyze and engage their customers via mobile apps providing strategic tools for their business.

Summary …

iBeacon technology is extremely powerful and flexible, so engineers, marketers, and others have the opportunity to create new important applications to improve people’s lives and to create business value for big and small companies. But don’t worry about the innovative new big brother. Instead of crying ‘Stop bothering me!’ just turn Bluetooth off.

I’m sure that apps of serious retailers will offer some options to choose the kind of information you want to receive. If not they are at risk that customers will delete the app, block information flow, or in a worst case scenario, say Good Riddance to the company.

Related links …

iPhone’s Dining Habits

Mystic signs of progress

About Bluetooth

List of BT Smart Devices

Thanks for visiting my blog beacon.





Air Display by Avatron

28 11 2013

AirDisplay by Avatron Software Inc., USA, transfers the screen content of a Mac or a Windows PC to the iPad or the iPhone if computer and iOS device are within the same WiFi network. Either it’s used as an extension to the computer’s screen showing windows which are dragged into an invisible area on the computer or just control the computer via the touchscreen of the iOS device.

Installation …

There is an iOS app (paid version) and a desktop companion app (free) which have to be installed the devices. Once the app is launched on both devices the screen content of your computer is transferred to your iOS device.

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Controlling the computer can be easily done by just tapping on controls. The menu of Air Display on the computer allows to select the iOS device on which the computer’s screen is shown.

Applications …

AirDisplay can be effectively used for

  • GTD
    Filling your iPad screen with your utility apps, like iChat, Mail, iCal, and Calculator
    Initiating or controlling tasks on your computer while sitting in another room
  • Business
    Moving your iWork and Office tool palettes and inspector windows onto the iPad, and let your document fill the screen.
  • Office
    Carrying an extra monitor down the hall to a meeting.
    Helping a colleague without leaving the room by looking on his screen.

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  • Presentation
    Retrieving some information from a computer while sitting in a conference room.
    Note
    If you want the information to be shared with an audience this can be done by connecting the iPad to a beamer with Apple’s Digital AV Adapter.

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  • Administration
    Copying a locally saved document to a network storage to make it available for colleagues.
  • Writing a short note on the local workstation.

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  • Medicine
    Let a patient or family member watch a procedure on a wireless video monitor.
  • Real estate or Sales
    Hand a client a mirrored display while you work at the laptop.
  • Programming
    Use the extra display area for such auxiliary development tools as Console, Terminal, and the Debugger.
  • Music
    Use your iPad as the ultimate control surface for Logic or Pro Tools.

AirDisplay 2 …

In November 2013 Avatron released AirDisplay 2 (which is quite expensive but worth buying) with these added features:

  • AirDisplay 2 now connects up to 4 iPads simultaneously to create unique presentations you drive from your Mac to start training sessions or presentations.
    This multi-client support will also be available for Windows in the near future.
  • New streamlined and iOS 7-ready interface
  • Improved performance

Summary …

AirDisplay is a useful tool for establishing ad-hoc connections to computers within the same WiFi network. The mobility within an office is no longer restricted when using AirDisplay on an iPad.

Your desktop is always with you.

Other products of this reliable company continuously updating it’s products are Air Login, Air Sharing, and Print Sharing. See my review of Air Sharing below.

Related links …

Presentation, Presenting with iPad (1)

Air Sharing, iWebDAV Connection

Remote Control, TeamViewer

Remote Control, AirLogin

Thanks for taking my blog into your viewing screen.





Speed Test

25 08 2013

Nature with it’s electromagnetic waves traveling with the speed of light helps us to retrieve information from the internet pretty fast even if the way data is taking is by far not the shortest possible.

Using a link from within an app a website opens after about 3 sec including the opening of Safari browser. It’s quite fast compared to a bus, a car, a high speed train, or even an aircraft.

The speed of light …

If there is a cellular connection to the Internet data can be transmitted without using a medium in contrast to sound which needs the air or the earth to propagate and to transmit information like the cry ‘Help, help’.

Electromagnetic waves transfer data in vacuum at the speed of light. None of Apple’s innovative techniques can make it faster. It’s a law of nature (a universal physical constant) found out by

Ole Rømer first demonstrated in 1676 that light travelled at a finite speed (as opposed to instantaneously) by studying the apparent motion of Jupiter’s moon Io. In 1865, James Clerk Maxwell proposed that light was an electromagnetic wave, and therefore travelled at the speed c appearing in his theory of electromagnetism. In 1905, Albert Einstein postulated that the speed of light with respect to any inertial frame is independent of the motion of the light source, and explored the consequences of that postulate by deriving the special theory of relativity and showing that the parameter c had relevance outside of the context of light and electromagnetism. After centuries of increasingly precise measurements, in 1975 the speed of light was known to be 299,792,458 m/s with a measurement uncertainty of 4 parts per billion. In 1983, the metre was redefined in the International System of Units (SI) as the distance travelled by light in vacuum in 1/299,792,458 of a second. As a result, the numerical value of c in metres per second is now fixed exactly by the definition of the metre.

Within media like cables it’s slightly slower, about 90 km/second (324,000 km/h or 201,324 miles/h).

With the speed of light you would need

From geostationary sattelite to earth 119 ms
From Sun to Earth 8.3 min
Across the Milky Way 100,000 years

And from Cupertino (Apple’s Headquarter) to Cologne in Germany?
Well that’s a problem. The app Google Maps showed me neither the way nor the distance. But there is a more severe problem: Light propagates linear. So a light beam would’t go the way to Cologne.

Internet connection …

If you connect your device to the Internet data is transferred via a couple of stations.

With the app Nice Trace the way the data takes from source (the server where you get the data from) to destination (your iPhone or iPad) can be reported.

This is the way my website http://iNotes4You.com is transferred to my device.

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Measuring the speed …

I want to compare the apps

SpeedTest by Ookla, USA

http://www.ookla.com/

Speed Test by Russian Internet Solutions LLC

http://www.appannie.com/app/ios/qip-speed-test/

cnLab Speed by cnLab AG Swiss

http://www.cnlab.ch/speedtest/

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My home configuration is a Cable Internet Connection from German provider UNITYMEDIA with a Cisco Modem and Apple’s router AirPort Extreme working on 802.11 a/b/g/n standard in the 5 GHz band. The device was an iPad 3rd Gen.

To eliminate ups and downs of the data transfer speed I measured the transfer rate for downloads under the following conditions:

50 repeated measurements
every day for one month at 8 am, 1 pm, and 9 pm

The apps used different test servers.

To compare the results I calculated the mean value of all measurements for each app.

Do the measured values come close to the everyday usage of your device with all the ups and downs of the internet connection?

Yes, they do.

Here is the result of using the app FTP Client PRO by Anders Havn with which I downloaded a file of 305 MB file size under the same conditions described above.

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Here are mean values of all the results I took over a period of one month:

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An alternate app …

If you are interested in an app which combines speed test with network analysis try

Net Analyzer by Jiri Techet

This perfect universal All-In-One app gives you all informations about a network including standard tools such as ping, traceroute, port scanner, whois, and beyond providing geolocation for all discovered servers.

Additionally I was impressed of Jiri’s perfect website for mobiles.

See this gallery to get an overview of the features:

This slideshow requires JavaScript.

Summary …

The results of all apps are within +-4.5 %. Differences may be caused by the different test servers used during measurements. All apps do what they are intended to do but cover just one functionality except Net Analyzer by Jiri Techet.

Thanks for visiting http://iNotes4You.com.





VPN with iOS Devices (2)

13 06 2013

My first article about this topic explained the basics of a VPN connection between a device outside your local area network and a computer inside of it. All necessary settings for firewall and iOS device are explained in this article.

Step 1 Configuring the firewall

Many of the VPN tunnel configuration settings in the VPN client on iOS devices or Mac OS X are not configurable by the user.
So it is very important to exactly configure the settings on the firewall to match the settings required by the VPN client on the iOS device or MAC OS X.

In web-interface of the Watchguard XTM firewall go to VPN – Mobile VPN with ipSec and click Add.

After finishing the configuration of the Mobile User VPN Group users have to be configured in a next step. If you define a user don’t forget to assign him to the group (here ‘Apple’) at the bottom of the dialog.

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If you want to use a configuration file (.wgm) for mobile devices which can be generated via Watchguard UI, send this file via E-Mail to your mobile device. On the mobile device tap on the attachment and select ‘Watchguard’ from the apps menu of the ‘Open in’ command. This will open the Watchguard configuration app. This app is solely for creating a profile containing the right settings.

I recommend to configure the device manually because it’s easy and a download of Watchguard’s app from Apple’s App Store is not needed.

Step 2 Configuring an iPad or iPhone

Configure the profile directly on the device …

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App controlled installation …

Tapping on the WGM file attachment opens Watchguard’s iOS app and you can install the configuration as an unsigned profile.

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Step 3 Testing the connection via WiFi or 3G

To access a resource from outside the LAN via VPN go to Settings on your mobile device and activate VPN. After a successful connection a VPN icon is displayed in the status bar.

When connected your device will behave as if it is part of the LAN. So any app on your mobile device you use inside the LAN can also be used when connected via VPN.

But keep in mind: That’s only valid for accessing files.
What you cannot use are apps which require the device located in the same network.

Example:
Consider the app Printer Pro. You can print documents saved on the mobile device using a printer connected to a computer in your LAN. This won’t work when connected via VPN because apps on your computer do not send information about available printers to your mobile device. This happens only if you are a real, not a virtual member of the LAN.
The option ‘Open on my PC’ provided by the app ‘Fingerprint’ is available if the device is a real member and disabled if there is a virtual connection to the LAN.

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I myself use the app FileBrowser to access files on remote computers.

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Summary …

Using a VPN connection provides security.
The participating devices have to authenticate before a secure connection can be established.
All data will be strongly encrypted before transfer over the unsafe internet starts.
To connect you just have to set the VPN slider to ON.

Thanks for flying with http://iNotes4You.com.





VPN with iOS Devices (1)

11 06 2013

Think about masked figures walking on the Broadway.
They are using public roads but you cannot identify them and you don’t know what’s going on inside their brain.

That’s the idea of establishing a Virtual Private Network (VPN) where the data stream uses the public internet highways but cannot be read by anyone. Capsule encrypted information in an ordinary overcoat and decrypt it by using a mutually agreed foreign language.

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This image shows the requirements of a typical configuration for private or small business use.

  • Firewall
  • Mobile device
  • Free Dynamic DNS account
  • Computer in a LAN you want to have connect to

Apple’s OS X for Mac and iOS for iPhone, iPad, and iPod Touch include a native Cisco IPSec VPN client. You can use this client to make a secure IPSec VPN connection to a firewall and the devices behind it. To do this, you must configure VPN on your firewall device to match those on the iOS or Mac OS X device.

Following the KISS principle I want to describe how to connect an iOS device with the LAN using the integrated Cisco client.

KISS
KISS = Keep it simple, stupid
A design principle noted by the U.S. Navy in 1960 that states that most systems work best if they are kept simple. Unnecessary complexity should be avoided.
Variations of this phrase are:
Keep it simple sir, Keep it simple and straightforward, Keep it short and simple, Keep it simple or be stupid

Why VPN …

Using a VPN connection provides security.
The participating devices have to authenticate before a secure connection can be established. All data will be strongly encrypted before transfer over the unsafe internet Autobahn starts.

You may think that there are apps connecting you with your devices at home with nearly zero configuration e.g. TeamViewer. That’s true but these apps don’t allow simultaneous connections of more than one device. Others like VNC Server/Viewer allow concurrent connections but their free versions do not support encryption. Additionally the firewall has to be configured for Port Forwarding.

So the best practice is to use VPN without additional licensing costs and nearly the same expenditure of time for setting up the virtual private network.

The basics …

Refer to the following articles about basic terms and functionalities of networking:

Network (1) Addressing

Network (2) Apple Airport router

Network (3) Port Forwarding

Your Internet Service Provider (ISP) usually assigns varying IPs. This would prevent a suitable usage of VPN. If this would happen with addresses in real life a postman could not deliver your mail. However there is a simple and free solution by using Dynamic DNS services offered by No-Ip.com or other providers.

From a Dynamic DNS provider you will get a hostname, not an IP address. A device from outside your LAN first contacts the DDNS provider to evaluate your actual WAN IP address. Your mobile device can now locate your LAN in the internet and establish a connection.

It’s quit simple to get an account at No-Ip.
Sign in and you get an E-Mail with a confirmation link.
Fill out the form for Dynamic DNS and you get a hostname like ‘user.no-ip.org’.
This constant hostname will replace the varying WAN IP of your home/small business network.
How does No-Ip get your WAN IP? Well, you have to install the free No-Ip Dynamic Update Client on one of your computers inside the LAN. This client updates your changing IP at No-Ip’s servers. Don’t switch this computer off to ensure that No-Ip knows your WAN IP at any time.

The Watchguard Firewall XTM …

Watchguard Inc. is located in Seattle, USA.
The company I work for uses Watchguard products without any problems since many years.

The firewall serves as a gateway for the LAN managed by Windows 2008 servers. Colleagues must have a secure access to these resources.

A running VPN connection …

The following steps illustrate the principles of a VPN client-server interaction in simple terms found on Wikipedia. For IP addresses refer to the above shown graphics.

Assume a remote host with public IP address 1.2.3.4 wishes to connect to a server found inside a company network. The server has internal address 192.168.1.10 and is not reachable publicly. Before the client can reach this server, it needs to go through a VPN server / firewall device that has public IP address 5.6.7.8 and an internal address of 192.168.1.1. All data between the client and the server will need to be kept confidential, hence a secure VPN is used.

01 The VPN client connects to a VPN server via an external network interface.

02 The VPN server assigns an IP address to the VPN client from the VPN server’s subnet. The client gets internal IP address 192.168.1.50, for example, and creates a virtual network interface through which it will send encrypted packets to the other tunnel endpoint (the device at the other end of the tunnel). This interface also gets the address 192.168.1.50.

03 When the VPN client wishes to communicate with the company server, it prepares a packet addressed to 192.168.1.10, encrypts it and encapsulates it in an outer VPN packet, say an IPSec packet. This packet is then sent to the VPN server at IP address 5.6.7.8 over the public Internet. The inner packet is encrypted so that even if someone intercepts the packet over the Internet, they cannot get any information from it. They can see that the remote host is communicating with a server/firewall, but none of the contents of the communication. The inner encrypted packet has source address 192.168.1.50 and destination address 192.168.1.10. The outer packet has source address 1.2.3.4 and destination address 5.6.7.8.

04 When the packet reaches the VPN server from the Internet, the VPN server decapsulates the inner packet, decrypts it, finds the destination address to be 192.168.1.10, and forwards it to the intended server at 192.168.1.10.

05 After some time, the VPN server receives a reply packet from 192.168.1.10, intended for 192.168.1.50. The VPN server consults its routing table, and sees this packet is intended for a remote host that must go through VPN.

06 The VPN server encrypts this reply packet, encapsulates it in a VPN packet and sends it out over the Internet. The inner encrypted packet has source address 192.168.1.10 and destination address 192.168.1.50. The outer VPN packet has source address 5.6.7.8 and destination address 1.2.3.4.

07 The remote host receives the packet. The VPN client decapsulates the inner packet, decrypts it, and passes it to the appropriate software at upper layers.

Overall, it is as if the remote computer and the server are on the same 192.168.1.0/24 network or in other words as if you are sitting in the office. VPN extends a private network across the public internet. Data are shared as if they were an integral part of the private network.

Continue reading about VPN. My next article describes the configuration of the firewall and the iPad/iPhone.

Thanks for visiting http://iNotes4You.com.








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