IPv4 versus IPv6 :: Understanding : Their : Basic : Differences.

Most businesses and networks today use IPv4 as their network addressing standard. With the exception of some DoD and government agencies few people have adopted IPv6. But what is so different about IPv6 versus IPv4? In this post we compare the differences between IPv6 and IPv4 and review some of the basics of what makes up an IPv6 address.

IPv4 is the current addressing standard on the Internet today. An IPv4 (or IP version 4) address is made of of four parts or octets, each containing 8 bits (hence the name octet). Each octet can represent a binary number from 0 through 255. So with this in mind there can be 4,294,967,296 possible ip addresses.

The table below shows a break down of a common IPv4 address into binary broken down by octet:

192								168								1								100
1	1	0	0	0	0	0	0	1	0	1	0	1	0	0	0	0	0	0	0	0	0	0	1	0	1	1	0	0	1	0	0

An IPv4 address is 32 bits long. Compare this to an IPv6 address which has 128 bits.  It's huge in comparison!

The way an IPv6 address is written is different also.   An IPv6 address has eight 16-bit sections, written in hexidecimal. Here is an example of an IPv6 address:

(FE80:0000:0000:0000:1111:2222:3333:4444)

Writing IPv6 addresses can be a bit daunting as they are 4 times as long as what we are used to.  Luckily IPv6 does come with some shortcuts in the annotation.   We can write the above address like this:

FE80::1111:2222:3333:4444

Anytime you have sections of contiguous zero bits, these can be shorten to double colons. So anytime you see a set of two colons in a row you know everything in between is zero bits.  NOTE: only one set of zeros can be replaced by double colons in an IPv6 address.

Making IPv6 Less Scary.

Another way an IPv6 address can be written is by taking the last 32 bits of the address and writting them as an IPv4 address.  This makes IPv6 a lot less intimidating when you look at it this way.  Here's an example:

FE80::192.168.1.100

Other Difference Between IPv4 and IPv6

There are more differences between the two addressing standards.  With IPv4, the "CLASS" of an address can be figured out by the first octet.  For example:

CLASS A (0.0.0.0 through 126.255.255.255)

CLASS B (128.0.0.0 through 191.255.255.255)

CLASS C (192.0.0.0 through 223.255.255.255)

CLASS D (multicast 224.0.0.0 through 239.255.255.255)

CLASS E (experimental 240.0.0.0 through 255.255.255.255)

Also, in IPv4 there are special addresses:

Loopbacks (127.0.0.0 through 127.0.0.255

RFC 1918 private addresses (10.x.x.x, 172.16-31.255.255, 192.168.x.x)

DHCP services not available (169.254.x.x)

Compare this to IPv6.

With IPv6 the first several bits describe an IP address "TYPE".  (remember we are talking about the first couple of "bits" in the address) For example:

010 - Unicast addresses for service provider allocation (4000::0 through 5FFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)

100 - Geographic IP addresses (8000::0 through 9FFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)

1111 1110 10 - link local addresses (FE80::0 through FEBF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)

1111 1110 11 - site local addresses (FEC0::0 through FEFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)

1111 1111 - multicast addresses (FF00::0 through FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)

Also, just like in IPv4,  IPv6 has some special addresses:

0::0 - unspecified
0::1.1.1.1 through 0::255.255.255.255 - IPv4 addresses
0::0001 - loopbacks

One final thing to note is that with IPv6 addresses, there are no broadcast addresses. Instead IPv6 uses multicast (or more accurately an "all hosts multicast address").

There are many more things that are different between IPv4 and IPv6. The more you learn about IPv6 the less intimidating it becomes. There are plenty of booka and RFC's about IPv6. Check it out and start becoming familiar with IPv6 now. The sooner you know it the better off you'll be in the long run.

Wireless Networking Basics.

An Introduction to Wireless Networking Standards

Way back in the early days of Wireless LAN (WLAN) development, there were a whole lot of folks trying different types of technologies to get wireless LAN communications to work.  Eventually some clear winners started to rise to the top and it was seen that interoperability between these technologies needed to exist.  It was this desire for inter-operation that eventually led to the creation of the wireless LAN standards that we have today.

But what are standards? Standards allow companies who build wireless networking devices know that their equipment will work with other manufacturer's wireless equipment. These standards are known today as IEEE 802.11a, 802.11b, 802.11g and the most recently ratified 802.11n.

Jamming out to the Band

2.4 Gigahertz Radio Band

I'm a big music fan and love a great band.  But today we're talking the radio frequency band.  This was thought by many to be the best band for commercial inroads to consumers.  The problem was and still is today is that its a very crowded RF band that's used by most home appliances including things like your microwave oven!

IEEE 802.11  - The Beginning of Wireless Networking Standards

At the beginning of any new technology,  inventors and technology developers tend to each take a different view on the specific technology at hand.   Wireless networking was no exception.  At that time players within the industry were looking at all types of methods of transferring LAN data without the use of wires.  As things evolved people realized their technologies weren't compatible with each other.   Again, Standards were needed to help move the technology to consumers and businesses.

To be honest standards don't always necessarily help get the technology to consumers quickly but it does ensure interoperability when it does get to the consumer.

Eventually certain functions, features and terminology that were common among each manufacturer got taken into the standard. It essentially became a popularity contest of features or terminology.

And the winners of the Wireless Networking popularity contest are:

• Access Point (AP)
• Basic Service Set (BSS)
• Extended Service Set (ESS)
• SSID (Service Set Identifier)
• WEP (Wireless Equivalent Privacy)
• Ad hoc Networking
• Infrastructure Networking

These are just a few terms that made it into the standard and all of these date back to the first 802.11 wireless networks.

The IEEE 802.11b Standard

IEEE 802.11b was the first major upgrade to the WLAN specification.  It was exciting news because this new standard ratified the wireless speeds up to 11Mbps.   The typical range for an IEEE 802.11b wireless network is about 100 feet (30 meters) or so depending on the environment.

Though the radio band was still over crowded, the 802.11b standard provided much needed relief for places not accessible by wire AND at a decent usable speed.

The IEEE 802.11g Standard

The next major improvement in WLAN networking in the 2.4 GHz RF band was IEEE 802.11g.  The "g" standard provided for even more network speed allowing up to 54Mbps AND was an easy upgrade for users of 802.11b as the new radios was backward compatible.

802.11g was able to achieve these cool new speeds through the use of Orthogonal Frequency Division Multiplexing (OFDM).  Multiplexing is a technology that allows you to take multiple pieces of data and combine them into a single unit to be modulated and sent over the same radio channel. What OFDM does is, it takes the data that needs to be transmitted and breaks it up into 52 sub-carriers that are all multiplexed together into a single data stream. Since there are 52 sub-carriers the final data stream can be sent at a slower rate, provide better reliability, sent a great distance and yet deliver more data.

5 Gigahertz Radio Band

While IEEE 802.11b was gaining wide acceptance in the 2.4 Gigahertz band, 802.11a was quietly getting some use in the 5 Gigahertz RF range.

IEEE 802.11a was 54 Mbps before 802.11g was even born

One of big advantages that 802.11a had over 802.11b was that it's speed was 54Mbps and operating in the less clutter 5 Gig RF band. It also used OFDM as  the modulation technique, so why didn't it take off like 802.11b did?

The biggest problem was that it wasn't compatible with devices that ran in 2.4Ghz band, namely 802.11b and g.  And it tended to be a bit more expensive (at the time).

Today's Wireless Networking technologies allow you to  operate in both frequencies.

IEEE 802.11n

IEEE 802.11n uses both OFDM and MIMO (multiple-in multiple-out) RF modulation techniques.  This allows for a maximum throughput of 600Mbps using four MIMO streams or 150Mbps using a single stream.   It operates in both RF bands, 2.4 GHz and 5 GHz and is backward compatible with the other standards.

The biggest problem with 802.11n is that it has only recently been ratified and many device manufacturers have not released firmware updates for the new standard.

All in all WLAN technologies have come a long way and are getting better every day.  They're more secure, faster, cheaper and more scalable.    It easy to see that every day we are becoming more and more connected.  And wireless networking has just begun to become part of the overall network infrastructure.

Mobile TFTP Server for the Data Center.

 Have you ever been in the data center, or out in some remote wiring closet, and realized you need a router config from your TFTP Server and can’t access it? Many people don’t want to leave a TFTP Server continually running on their network since it is not secure and it opens them up to unscrupulous bots or hackers. Unfortunately, that can leave you in a lurch when you need to access a router config file or binary image, and can’t get to it. Sometimes the security team prevents TFTP from traversing the network in the first place, so that even if you have a TFTP Server running, it’s blocked by the firewall.

Recently, I created an iPhone/iPad TFTP Server app to address exactly those problems. Using a mobile TFTP Server means you can carry it with you to the wiring closet or data center. This allows you to turn it on, copy over the configs or software you need over WiFi, and turn it back off when you are done.

One of the first questions people ask is “ok, but how do I get my files to or from my iPhone?”

Basically there are three main ways to get the files there:

• Standard TFTP put and get command.
•  Copying files using the built-in file copy within iTunes.
• One-click Dropbox download and upload.

So how would this work if you wanted to copy a config from one router, edit it slightly, and then copy that config back to a different router? Amazingly simple:

1)      Turn on the TFTP Server app on your iPad or iPhone.

2)      Log into the first router and copy the running config to the TFTP Server.

“copy run tftp” (Enter the IP address of the TFTP Server when prompted.)

3)      Upload that file into your Dropbox account by simply holding your finger on the file name for one second.

4)      Use a Dropbox editor like PlainText to edit the file.

5)      Copy the file from Dropbox back to your iPad/iPhone TFTP Server.

6)      Log into the second router and copy the config from your TFTP Server to either the startup or running config on your router.

“copy tftp start” or “copy tftp run” (Enter the IP address of the TFTP Server and name of the file when prompted.)

7)      Turn your iPhone/iPad TFTP Server back off.

That’s it!

One of the great things about the TFTP protocol is that it is easy to configure appropriate network access. A TFTP client uses port UDP port 69 to contact the TFTP Server, and then data is transferred between two random high UDP ports greater than 1024. According to the initial standard, the UDP packets are restricted to a block size of 512 bytes. This is what first limited file transfer sizes to 32 Megabytes, because each packet contains a 16 bit block counter. (512 x 65535 = 32 MB) Later, RFC 2348 allowed for larger block sizes. By increasing the block size to 1468 (the maximum that allows staying under the Ethernet MTU size), our mobile TFTP server supports file sizes larger than 32 MB.

Mobile tools for network engineers will likely continue to be the trend as many people are simply tired of lugging around a laptop everywhere. If all your networking tools could run on your mobile device, why would you use anything else?

Using PING to Troubleshoot Network Problems.

The two most used tools, and almost always the first used to diagnose a network problem are traceroute and ping. The results they return are however most often misunderstood or interpreted in a way that leads to an incorrect conclusion.

Let's take the ping utility specifically. The common mistakes that is made is that whatever the ping result is, is due to the target of the ping. For example, if there is no ping response; conclude that the site is down. Or if there is packet loss or long return times, conclude that it is because of some problem with the target address. While both those outcomes could be the case, far more often than not, they are completely the wrong conclusions to draw.

The common causes of this misinterpretation are:

1. Ping sends a packet to the destination address that typically will traverse several other network points to get there. A problem at any one of those points will cause a non response to the ping query
2. In many cases web sites and other servers sit behind firewalls, and many, if not most, firewalls block ping packets. So while web traffic may reach the site, ping packets may not.
3. The ping packet has a source (the system initiating the ping) as well as a destination, it may be that the source does not have a correct route path to the destination, or that the destination does not have a correct return route path to the source. This could be because of specific firewall rules, an error in the route tables 'somewhere' along the data path, or a specific routing policy deliberately put in place to block access.

The traceroute command can be used to help detect if 1. or 3. are the cause of the problem, which has its own issues, but more on that later. A positive result from either telnet and tcptraceroute will conclusively rule out 2. as a possible case.

Telnet can be used to open a connection any any port, not just the telnet default port. A successful telnet connection where ping has failed is proof positive that a firewall is preventing access to ping packets. Here is an example:

$ ping cisco.com PING cisco.com (198.133.219.25) 56(84) bytes of data.

--- cisco.com ping statistics ---

6 packets transmitted, 0 received, 100% packet loss, time 5008ms

$ telnet cisco.com 80

Trying 198.133.219.25...

Connected to cisco.com.

Escape character is '^]'.

You can see that the ping packet failed, but that telnet to port 80 succeeded in connecting to the server.

So too with tcptraceroute on port 80:

$ tcptraceroute cisco.com 80

traceroute to cisco.com (198.133.219.25), 30 hops max, 40 byte packets

1 192.168.6.254 (192.168.6.254) 8.557 ms 10.624 ms *

....

15 cisco.com (198.133.219.25) 289.162 ms 237.972 ms 242.171 ms

Another common error using ping is that the results of just a few ping tests are indicative of the condition of a data path. It may be true, but such a conclusion can only be relied upon over a statistically meaningful sample size. Also, to be truly accurate, the distribution of packets responses outside the acceptable level needs to be known.

For example, as single ping test of four packets where one packet is dropped, can not, in any meaningful way, be used to conclude that there is 25% packet loss on that circuit. Ten thousand ping tests, over several hours where there is say 5% lost has far more meaning; however consider if the test was done over 24 hours, and for one hour the target site was down. The 100% loss during that hour looks like a general 5% packet loss over 24 hours.

It is therefore important to review the record of the ping test and see if the distribution of any packet loss is regular or confined to a specific period, before a real conclusion can be drawn.

A third common error is that the cause whatever is result is gained is due to the target site. For example, say 5% packet loss was found when pinging 3com.com, this by no means indicates that the problem lays with that site, rather, the problem could be with any of the points along the data path to that site, inclusive the source (my own computer):

$ traceroute 3com.com traceroute to 3com.com (192.136.34.41), 30 hops max, 40 byte packets

1 192.168.6.254 (192.168.6.254) 10.285 ms 13.316 ms 14.440 ms

2 129.1.233.220.exetel.com.au (220.233.1.129) 132.994 ms 135.387 ms 136.312 ms

3 241.0.233.220.exetel.com.au (220.233.0.241) 137.192 ms 141.296 ms 162.018 ms

4 10.0.1.1 (10.0.1.1) 168.530 ms 174.358 ms 176.908 ms

5 38.2.233.220.exetel.com.au (220.233.2.38) 177.729 ms 188.233 ms 189.122 ms

6 359-ge-0-0-0.GW5.SYD2.ALTER.NET (203.166.92.57) 197.691 ms 85.598 ms 156.625 ms

7 0.so-0-2-0.XR3.SYD2.ALTER.NET (210.80.33.189) 158.108 ms 159.430 ms 160.260 ms

8 0.so-4-3-0.IR1.LAX12.ALTER.NET (210.80.50.249) 305.124 ms 305.952 ms 306.775 ms

9 0.so-5-0-0.IL1.LAX9.ALTER.NET (152.63.48.65) 313.518 ms 321.047 ms 321.868 ms

10 0.so-5-0-0.XT1.SAC1.ALTER.NET (152.63.0.98) 405.111 ms 406.359 ms 407.241 ms

11 GigabitEthernet6-0-0.GW9.SAC1.ALTER.NET (152.63.55.73) 331.091 ms 337.600 ms 341.527 ms

12 eds-gw.customer.alter.net (63.114.61.154) 357.930 ms 287.765 ms 310.755 ms

13 205.141.209.3 (205.141.209.3) 311.606 ms 312.502 ms 313.587 ms

14 10.231.1.2 (10.231.1.2) 341.277 ms 342.101 ms 342.931 ms

15 205.141.209.133 (205.141.209.133) 344.380 ms 345.861 ms 346.689 ms

16 ip-192-136-34-41.ip.3com.com (192.136.34.41) 261.317 ms 266.998 ms 346.689 ms

You can clearly see the number of hops the data must traverse. In this case there is no evidence of any problem along the data path. But if the traceroute looked like this:

$ traceroute 3com.com traceroute to 3com.com (192.136.34.41), 30 hops max, 40 byte packets

1 192.168.6.254 (192.168.6.254) 10.285 ms 13.316 ms 14.440 ms

2 129.1.233.220.exetel.com.au (220.233.1.129) 132.994 ms 135.387 ms 136.312 ms

3 241.0.233.220.exetel.com.au (220.233.0.241) 137.192 ms 141.296 ms 162.018 ms

4 10.0.1.1 (10.0.1.1) 168.530 ms 174.358 ms 176.908 ms

5 38.2.233.220.exetel.com.au (220.233.2.38) 177.729 ms 188.233 ms 189.122 ms

6 359-ge-0-0-0.GW5.SYD2.ALTER.NET (203.166.92.57) 197.691 ms 85.598 ms 156.625 ms

7 0.so-0-2-0.XR3.SYD2.ALTER.NET (210.80.33.189) 758.108 ms 759.430 ms *

8 0.so-4-3-0.IR1.LAX12.ALTER.NET (210.80.50.249) * * 806.775 ms

9 0.so-5-0-0.IL1.LAX9.ALTER.NET (152.63.48.65) 813.518 ms * 721.868 ms

10 0.so-5-0-0.XT1.SAC1.ALTER.NET (152.63.0.98) * 1406.359 ms 1007.241 ms

11 GigabitEthernet6-0-0.GW9.SAC1.ALTER.NET (152.63.55.73) 731.091 ms 737.600 ms 1341.527 ms

12 eds-gw.customer.alter.net (63.114.61.154) 357.930 ms * *

13 205.141.209.3 (205.141.209.3) 811.606 ms 812.502 ms 813.587 ms

14 10.231.1.2 (10.231.1.2) 741.277 ms 742.101 ms 1342.931 ms

15 205.141.209.133 (205.141.209.133) * * 746.689 ms

16 ip-192-136-34-41.ip.3com.com (192.136.34.41) 761.317 ms 866.998 ms *

It would be reasonable to conclude that there was some serious problem between hop 6 and hop 7 that is causing the ping test to return its lossy result.

How to Become a Network Engineer.

So you want to become a network engineer?  I have a lot of people ask that exact question - "How can I get into Networking?"  or "How do I become a Network Engineer?".  I personally think that anyone who asks these questions and has a desire to learn about computer networks is doing themselves a big favor that will benefit them for the rest of their lives.

There are many reasons to want to work as a network engineer, great pay, great company, good benefits, or to simply work with great technology. But getting yourself into a position like this may not always be the easiest thing to achieve.   In today's market competition is fierce.   in this post we will list some ways that may help you get that cool network engineering job and potentially boost your career.

Network Engineer Training and Certifications

The first and most direct way to easily get a job working as a network engineer is to do some self study and get a vendor certification like a Cisco Certified Network Associate (CCNA).  Anyone who already has a certification in Microsoft or Novell knows these certification tests are not easy.  And Cisco tests are, in my opinion, the hardest tests out there.  The current CCNA test not only will test your book knowledge on the theory of computer networking, TCP/IP, and the OSI model, but will also test  your "practical knowledge" of actually performing the task that may be called upon you as a junior network engineer.  The one thing that set Cisco tests apart from other vendors are the router simulations. Router simulations are very common on the CCNA and are very realistic. For this reason people who pass a Cisco exam not just good test takers, they are know their stuff.  To pass the CCNA I would highly recommend starting with one of the great books on the CCNA. Go the book store and find a book that keeps your attention and is easy for you to read.  Next, invest in a practice exam like one from Pass4Sure, or Test King. Test questions are worded very tricky and taking these practice tests will guarantee you getting the multiple choice stuff correct.  Finally, you will need to work on your router skills.   Either purchase a router on ebay or download GNS.  GNS is a free router simulator that can help you immensely and best of all its free.  These three things combined will land you that certificate, they will increase your value in the work place, and will most likely get in the door to do some real hands on networking.  Of course you still have to pass the interview 

On the Job Training

Sometimes poring over the Career Builder web site or the Monster job boards can yield you a nice selection of network jobs you may qualify for without having a certification.  These jobs will typically pay less however will offer the opportunity to learn and may provide training to advance yourself to get a CCNA.

College

Colleges today recognize the demand for skilled I.T. people in the work place and have started to establish certification programs that will allow you to earn your CCNA or CCNP which will definitely launch you in the the networking hot seat.  The benefit of College programs is that these often qualify for grants and loans that may not otherwise be available.

Military

This option seems to be overlooked and is last on the list of where to find quality training, but really this should be one of the first on many peoples list.   The biggest problem is that working in the Army, Air Force, Navy or Marines is often misunderstood.   Each branch is significantly different and each has their own training and benefits.

Most people envision Hollywood movie footage of "Black Hawk Down" living in the dessert eating C-rations.   Of course those jobs, locations, and duties do exist,  however life in the military is far different and the educational benefits are tremendous!  The US military offers some great programs that will get your hands on some of the latest technology and networks that you can find in the civilian world.  No where else can you find a place that will immediately give you a paycheck, provide you with all the food you can eat, comfortable living quarters, new clothes and a world class education.

Summary

There are lots of ways for motivated people to change their life, and land a job as a network engineer.  Doing so will allow you to make a good living and work with some awesome technology.  Getting there is up to you. Whether it be self-study, class-room training, college or the military, if you truley want to work as a network engineer there is a way.  You just have to do it.

Google Limits Free Access To News Articles!

Google is to limit the number of news articles users can read for free on its website.

The search engine said it was changing its First Click Free programme so that readers would not be able to look at more than five pages in one day.

The move follows scathing criticism of Google by Rupert Murdoch over the way it provides free access to newspaper articles in his News Corp media group.

Some users have been able to get around paying subscriptions or registration by accessing news articles through Google. But after the changes, users who click on more than five articles in a day may be routed to payment or registration pages, Google said..

Google’s senior business product manager Josh Cohen said: “Previously, each click from a user would be treated as free.

“Now, we’ve updated the program so that publishers can limit users to no more than five pages per day without registering or subscribing.”

Mr Murdoch had threatened to block Google access to his newspaper websites.

He has accused news aggregators of “feeding off the hard-earned efforts and investments of others”.

“To be impolite it’s theft,” he said.

“Good journalism is an expensive commodity.”

Mr Murdoch says he intends to extend charging for access to some of his newspapers on the web.

The Wall Street Journal has already moved behind a pay-wall.

“We intend to expand this pay model to all our newspapers in the News Corp stable: the Times of London, The Australian, the rest,” he said.

“Some critics say people won’t pay. I believe they will.”

Manage Windows 7 Themes with the Windows Theme Manager

Most Windows 7 users are familiar with the concept of Windows themes to light up their desktops. However, using the inbuilt windows 7 desktop theme manager has some major limitations. To remove these limitations we have come out with a single click to install Windows 7 theme manager.

Windows Theme Manager will let you manage all your windows 7 themes in “One Click”. It comes with 100’s of free High quality windows seven themes which you can get direct access to.  One of the main advantages of the Windows 7 Theme manager is that it connects to an internet database of themes with hundreds of themes and is constantly updated.  This makes sure that you have access to hundreds of professionally designed themes all the time.

The inbuilt theme catalogue is updated via the internet any time the program starts. This guarantees you access to the latest themes. This program is bound to breathe new life into your desktop.

You can switch between themes at your liking in just a single click. On the “Install theme” tab you get easy access to all themes installed on your system, sorted by categories. You can select one or more themes for deletion. This way you can keep your themes directory uncluttered.

The theme manager provides you with these benefits:

• Save time with our one click themes install. Any theme can be install with just one click.
• Easy access to hundreds of professional quality themes
• Easy management of themes via our intuitive GUI
• Change your theme in just one click. No more clicking several buttons to get new theme. We do all the hard work for you by collecting and updating all the themes for you.
• Delete one or more themes from your computer in just two easy clicks

For more information and a free download of the Windows 7 Theme Manger please visit www. www.windows7themesfree.net

How to install Windows 7 with a USB flash drive.

Microsoft Windows 7 comes pre-installed on most laptops and PCs but there will be a time when you might want to reinstall the operating system or maybe you're building a machine from scratch. Installing Windows from a USB drive is by far the easiest and neatest way of doing so and here's a step by step guide on how to do it.

There is a geeky command line method of creating a bootable USB drive but Microsoft has a free tool for this task which is much quicker and simpler.

You will need a USB drive with a minimum 4GB of space and a Windows ISO file.

The easiest thing to do is download the correct ISO file from the internet. Heidoc.net has downloads available for the different versions of Windows 7 - ideally make sure the ISO matches the version which is associated to your product key. However, we have included a trick which will allow you to choose which version you want to install.

Alternatively you can create an ISO file from a Windows disc if you have one. How to geek has a guide on this.

NOTE: The drive will be formatted so make sure you don't have any files on the drive that you wish to keep.  

Step One

Once you have your USB drive and ISO file ready to go. Click the following link and download and install Microsoft's Windows 7 USB/DVD Download Tool.

Step Two

Insert your USB drive and run the Windows 7 USB download tool - a shortcut should have appeared on your desktop.

Step Three

Select your ISO file to install onto the USB drive and click 'Next'.

Step Four

The software gives you a choice of burning the ISO file to a USB drive or DVD. For the purposes of this guide select 'USB'.

Step Five

Now select the USB drive you wish to use from the drop down box and click 'Begin Copying'. You will be presented with a warning that the USB drive needs to be erased, click 'Erase USB Device' and then 'Yes' when asked whether you are sure. Your bootable Windows 7 USB drive will now be created.

Step Six

If you wish you be able to select the version of Windows 7 to install from the one USB drive then open the drive in Windows Explorer and delete the 'ei.cfg' file found in the 'Sources' folder.

How to remotely access a Windows 8 PC.

One of the useful things about Windows 8 is that you can connect with people in lots of useful ways. Linking all your contacts so you’ve got a range of options when you need to get hold of a friend is one thing; being able to help them solve a problem with their Windows 8 PC just by being connected through email and the web takes it to another level.

You might have heard of remote assistance before. It’s a way of one person logging into another’s computer or laptop (with their permission and for a specific session only), helping diagnose a problem and attempting to fix it for them. Technical support staff for computer companies and internet service providers sometimes use remote assistance in this way. Complete Guide to Windows 8.

Soluto uses remote desktop - the technology that allows someone to securely log on to your PC - in a slightly different way. It offers the sort of troubleshooting and diagnosis we’ve just described, but it also lets you tinker with remote Windows 8 computers to improve their everyday performance.

This means you can you keep a benign watchful eye over the state of a Windows 8 PC you may well be called upon to fix when things go wrong, so you’ll have an idea of what the problem might be. And if it’s something as easily remedied as the antivirus software not being kept up to date, leaving the computer vulnerable to infection, you can prevent the PC encountering such issues in the first place.

Windows 8 remote assistance: Use Soluto to troubleshoot PC problems

Step 1. To get started with Soluto, install the app from the Windows 8 Marketplace. It’s free. You’ll need to enter your email address – the same one you use for other things is fine. There’s no need to create a specific Soluto email address unless you wish to.

Step 2. Click in the space underneath the person’s graphic, type in a name and click ‘Add this person’. Enter their email address and add your photo or phone number if you want to reassure the person you’re inviting to Soluto that it’s a legitimate offer of help.

Step 3. The recipient of the invitation now needs to follow the link in their email to download Soluto to their Windows PC or laptop. Once set up on the remote computer, Soluto informs the user that you are helping them with their computer. You’ll get an email notification, too.

Step 4. On your Windows 8 PC or tablet, you’ll now see that the avatar for the connected person is a darker blue, while other invitees are shown as a paler blue. Click on the connected person’s graphic to access their PC. Soluto indicates that you’re connected via Internet Explorer.

Step 5. You’ll see an overview of the PC itself, its age and operating system. Click on the Hardware option at the top of the screen to view component details. Scroll to the right of the screen to view details of any additional hard drives. A green tick next to a drive indicates that it’s healthy and does not need defragmenting.

Step 6. The Apps section lists installed programs. Any that need updating are clearly marked. Click on those you think should be updated. Many will only update when the PC is preparing to shut down or when it restarts. To signal that it knows to initiate the update, the Soluto message now changes to ‘update in progress’.

Step 7. Soluto suggests apps that may be useful to the user. Scroll to the right of the Apps screen and you’ll see details of browser adds-ons, free security software and utilities that could improve their computing experience. Click to install items you think will be worth having.

Step 8. Soluto allows you to offer support and remotely access up to five PCs for free. If you have more than one home computer, it can be useful to include these. To add more people, click on the lower portion of your Windows 8 screen and press Add to bring up the invitation list again.

Run 64bit Windows XP on a Windows 7 PC.

QUESTION I'm looking to build a PC for use as a Windows 7 Professional CAD workstation. It will probably have 8- or 16GB of RAM. I have legacy software running on XP. Can you tell me if all the RAM will be available in XP Mode? Anon

HELPROOM ANSWER The Windows XP emulation mode offered with Windows 7 Professional runs a 32bit version of XP. The maximum amount of memory available to the guest operating system is 3,712MB.

If you use another virtualisation program, such as the free VirtualBox from Oracle, you will be able to run 64bit guest operating systems, including Windows XP 64bit. However, you will need to purchase a copy of Windows XP 64bit to do so.

It's important to consider that with both options, your virtual Windows XP PC will use a pre-allocated chunk of system memory from your host PC. You wouldn't want to allocate too much system memory to XP Mode, since it would deplete the resources of your host Windows 7 operating system.

You don't say which legacy applications you need to run under XP. If it's your CAD applications that require XP, we recommend setting up a dual-boot system that allows you to run a native installation of XP at full speed. The graphics capabilities of a virtual Windows XP installation will be considerably slower than a native installation.

Given enough disk space, you could install both a dual-boot system and a virtualised system. This would enable you
to conveniently run your XP applications without rebooting, but with the option of booting into your native XP installation for intensive sessions where performance is key.

How to reinstall Windows 7 as an upgrade or a custom installation.

QUESTION Three years ago I bought an HP laptop running Vista with a free upgrade to Windows 7. The upgrade consisted of two discs: HP Upgrade Manager, which I had to run first, and a Windows 7 disc, marked 'For use only as an upgrade to a qualifying HP Windows 7 Upgrade PC'. The Windows disc has a valid Microsoft product key sticker. My overloaded laptop is now grindingly slow and it's time to reformat the hard drive and reinstall the OS.

Can I do this in the same way as the original upgrade, or will the fact Vista no longer exists on the computer cause problems? Anon

HELPROOM ANSWER Before starting this procedure, it's vital that you've backed up everything you need from your system. The Windows 7 upgrade disc should consider an existing installation of Windows 7 a valid operating system from which to 'upgrade'. Don't reformat your hard drive before you start. Instead, insert the Windows 7 upgrade disc and run the installation from Windows.

You can choose to complete either an upgrade or a custom installation. The upgrade option will perform what used to be known as a repair installation, leaving your programs and settings intact, but returning the operating system to its original state. You'll need to reinstall any Windows updates and drivers following the installation.

However, a custom installation won't clear out the bloat from the Registry. We'd advise opting for the custom installation. This will leave you with a fresh version of Windows, without your documents and applications, but with your previous installation backed up in a 'Windows.old' folder from which you can recover that data.

You may run into trouble if you wipe your hard drive before you begin the procedure. The upgrade key is unlikely to activate your installation if a valid upgrade hasn't taken place. There are workarounds for this, such as installing Windows 7 twice or employing a Registry hack to fool the system into thinking it's a valid upgrade. However, we recommend avoiding this; while no problems have been reported so far, it's feasible that Microsoft might flag up such activations as invalid in the future.

The HP Upgrade Manager disc contains versions of HP's preinstalled software that were previously compatible only with Vista. It's designed to manage the upgrade process for you. It may be wise to start by running this disc first as HP may have customised the installation discs, making them slightly different in operation from the standard Windows installation media.

Upgrading from 32- to 64bit Windows.

QUESTION I have recently upgraded my PC from XP to Windows 7 Ultimate 32bit edition. I understand that the disc and activation code can be used again, so how can I activate the 64bit version using a 32bit-labelled disc? Ron Hassett

HELPROOM ANSWER There is no way to perform an upgrade from a 32- to a 64bit version of Windows; instead, you need to complete a clean installation of Windows 7 64bit. However, if your disc contains only the 32bit edition, you can't use it to install 64bit Windows. (See also: Run 64bit Windows XP on a Windows 7 PC.)

If your copy of Windows didn't come with two discs (one 32bit, the other 64bit), you may find your product key isn't valid for a 64bit installation. This will depend on the exact version of Windows 7 you purchased and whether it's an upgrade, OEM or a full retail copy. Full retail copies should include a code for 64bit installations, but you'll still need the relevant disc – perhaps a friend has one you could borrow.

If you haven't already checked, ensure your processor supports 64bit operation.

If you're not sure, use the free CPU-Z utility. Look for support for EM64T in the section marked Instructions.

Read more: http://www.pcadvisor.co.uk/how-to/windows/3365474/upgrading-from-32-64bit-windows/#ixzz202NEWqrE

How to use Linux.

If you've only ever used Windows before, then getting to grips with another operating system, such as Linux, can be an intimidating task. However, very little about Linux is actually difficult to use. It's simply a different OS, with its own approach to doing things.

Once you learn your way around a Linux desktop, you're likely to find that it's no more challenging to work with than Windows or Mac OS.

• Microsoft Windows 7 review
• Microsoft Windows Vista review

In this guide I'll focus on Ubuntu, the most popular Linux distribution today. But Ubuntu is just one of many different flavours of Linux. Literally hundreds of distributions are out there, appealing to a broad range of users - from teachers and programmers to musicians and hackers.

Ubuntu is the most popular distribution because it's easier to install and configure than most others; it even comes in a few different versions, including Edubuntu and Kubuntu. If you happen to be running a different distribution, such as Fedora or OpenSUSE, you'll likely find that much of this guide still pertains to you.

For further reading check out our 'A novices guide to Ubuntu Linux' feature.

See also: Ubuntu 8.04 'Hardy Heron' review

• Visit PC Advisor's Linux News Spotlight

Welcome to Ubuntu

It's little wonder why Ubuntu is one of the leading Linux distributions for desktop PCs; it makes installing Linux simple. But once you have Ubuntu installed on your PC, what next?

The short answer is: whatever you like. Ubuntu may be free, but it's hardly a toy OS. If you can do something with Windows or Mac OS X, you can do the same thing with Ubuntu.

Figuring out how to do what you want isn't always obvious, however, and Ubuntu has its own concepts and quirks that set it apart from other OS'. Experience is usually the best teacher, but if you need a gentle push in the right direction, this guide offers a novice's tour of the Linux desktop - so fire up your Ubuntu system and follow along!

Exploring the interface

One of the first things you'll notice about your new Ubuntu system is that you need to log in each time you boot, giving the user name and password you specified during installation. If you prefer - and you're not worried about other people accessing your PC when you're not around - you can configure the system to log you in automatically from the 'Security' tab of the 'Login Window' panel of the ‘Administration' menu.

Even if you do that, however, don't forget your password; unlike in Windows, you'll need to enter the password again whenever you install software or perform sensitive administration tasks. (That may seem annoying, but it's an important part of Linux's famously high security.)

Read more: http://www.pcadvisor.co.uk/how-to/software/109861/how-to-use-linux/#ixzz202MH0Jpw