Troubleshooting and the Future of Networking

Introduction

Networks are the backbone of modern computing, connecting devices and allowing them to share resources and information. However, networks can sometimes malfunction, leading to frustrating connectivity issues. As an IT support specialist, it’s your job to troubleshoot these issues and get users back online as quickly as possible.

This tutorial will provide you with the essential skills and knowledge you need to troubleshoot common network connectivity problems. We’ll cover a variety of topics, including:

• Identifying common network problems
• Using troubleshooting tools
• Fixing connectivity issues on Windows, macOS, and Linux

By the end of this tutorial, you’ll be able to:

• Diagnose and resolve common network connectivity issues
• Use a variety of troubleshooting tools effectively
• Troubleshoot network issues on different operating systems

Common Network Problems

There are many different types of network problems that can occur. Some of the most common include:

• No internet connection: This is often caused by a problem with your modem, router, or internet service provider (ISP).
• Slow internet speeds: This could be caused by a number of factors, such as congestion on your network, outdated equipment, or interference from other devices.
• Dropped connections: This could be caused by a loose cable, a problem with your network adapter, or interference from other devices.
• DNS errors: These errors can prevent you from resolving website names and accessing websites.

Troubleshooting Tools

There are a number of tools that you can use to troubleshoot network problems. Some of the most common tools include:

• Ping: This tool is used to test if you can communicate with a specific device on the network.
• Tracert: This tool shows you the path that data takes to travel from your computer to another device on the network.
• Ipconfig: This tool displays information about your network adapter, including its IP address, subnet mask, and default gateway.
• Network diagnostics tools: Many operating systems come with built-in network diagnostics tools that can help you identify and fix network problems.

Fixing Connectivity Issues

Once you’ve identified the problem, you can start to fix it. Here are some tips for fixing common network connectivity issues:

• Check your cables: Make sure all of your network cables are securely plugged in.
• Restart your devices: Sometimes, simply restarting your modem, router, and computer can fix the problem.
• Update your drivers: Outdated network drivers can cause connectivity problems. Make sure you have the latest drivers for your network adapter.
• Change your DNS settings: If you’re having trouble resolving website names, you can try changing your DNS settings.
• Contact your ISP: If you’ve tried all of the above and you’re still having problems, contact your ISP for help.

Troubleshooting on Different Operating Systems

The specific steps for troubleshooting network problems will vary depending on your operating system. However, the general principles are the same. Here are some resources that you can use to learn more about troubleshooting network problems on specific operating systems:

• Windows: Microsoft Network Troubleshooting Guide: <invalid URL removed>
• macOS: Apple Support – Wi-Fi: <invalid URL removed>
• Linux: Ubuntu Network Troubleshooting Guide: <invalid URL removed>

Conclusion

Network troubleshooting can be challenging, but with the right skills and knowledge, you can diagnose and fix most common problems. By following the tips in this tutorial, you’ll be well on your way to becoming a network troubleshooting pro!

Welcome back. As you’ve seen, computer networking can be an incredibly
complicated business. There are so many
layers, protocols, and devices at play and
sometimes this means that things just don’t work
properly, no surprise there. Many of the protocols and devices we’ve covered
have built-in functionalities to help protect against some of these issues. These functionalities
are known as error detection and
error recovery. Error detection is
the ability for a protocol or program to determine that
something went wrong. Error recovery is
the ability for a protocol or program
to attempt to fix it. For example, you
might remember that cyclic redundancy
checks are used by multiple layers
to make sure that the correct data was received
by the receiving end. If a CRC value doesn’t
match the data payload, the data is discarded. At that point, the
transport layer will decide if the data
needs to be resent. But even with all of these
safeguards in place, errors still pop up, misconfigurations occur,
hardware breaks down, and system incompatibilities
comes to light. In this module, you’ll learn about the most common
techniques and tools you use as an IT support specialist when troubleshooting
network issues. By the end of this module, you’ll be able to
detect and fix a lot of the common network
connectivity problems by using tools available on the three most common
operating systems, Microsoft, Windows,
Mac OS, and Linux.

Network Troubleshooting with ICMP and Ping: Summary

This text delves into using ICMP (Internet Control Message Protocol) and the ping tool for network troubleshooting. Here are the key takeaways:

ICMP:

• Used by devices to communicate network errors back to the source of problematic traffic.
• Carries messages with types and codes specifying the error (e.g., destination unreachable, port unreachable).

Ping:

• Employs ICMP echo requests and replies to assess connectivity to a specific device.
• Provides output on round-trip time, packet loss, and other connection quality metrics.
• Commands differ slightly across operating systems, but core functionality remains the same.

Benefits:

• Diagnose basic network connection problems.
• Pinpoint the exact cause behind an error message.
• Troubleshoot initial network issues without advanced tools.

Remember:

• ICMP serves primarily for automatic communication between devices, but tools like ping bridge the gap for human interaction.
• Ping offers a simple yet powerful method for initial network troubleshooting.

Further Exploration:

• Delve deeper into command-line options for ping.
• Investigate specific error messages and their implications.

By understanding ICMP and ping, you gain valuable tools for diagnosing and resolving network connectivity issues. Remember, this summary provides a foundation. You can enhance your troubleshooting skills by exploring these areas further.

When network problems come up, the most common issue
you’ll run into is the inability to establish
a connection to something. It could be a server
you can’t reach at all, or a website that isn’t loading. Maybe you can only
reach your resource on your land and can’t connect
to anything on the Internet. Whatever the problem is, being able to diagnose connectivity issues is an important part of
network troubleshooting. By the end of this lesson, you’ll be able to
use a number of important
troubleshooting tools to help resolve these issues. When a network error occurs, the device that detects
it needs some way to communicate this to the source of the problematic traffic. It could be that a router
doesn’t know how to route to a destination or that a
certain port isn’t reachable. It could even be that the
TTL of an IP datagram expired and no further router
hops will be attempted. For all of these
situations and more, ICMP or Internet Control Message Protocol is used to
communicate these issues. ICMP is mainly used by a
router or remote host to communicate why
transmission has failed back to the origin
of the transmission. The makeup of an ICMP
packet is pretty simple. It has a header with a few fields and a
data section that’s used by a host to
figure out which of their transmissions
generated the error. The first field is
the type field, eight bits long, which specifies what type of message
is being delivered. Some examples are destination unreachable or time exceeded. Immediately after this
is the code field which indicates a more specific reason for the message
than just the type. For example, of the
destination unreachable type, there are individual codes for things like destination
network unreachable, and destination
port unreachable. After this is a 16-bit checksum that works like every
other checksum field we’ve covered so far. Next up is a 32-bit field with an uninspired name,
rest of header. You think they
could come up with something a bit
more interesting, but I can’t really
think of anything good. Who am I to judge? Anyway, this field
is optionally used by some of the specific types and codes to send more data. After this is the data
payload for an ICMP packet. The payload for an ICMP packet
exists entirely so that the recipient of the
message knows which of their transmissions caused
the error being reported. It contains the
entire IP header and the first eight bytes of the data payload section
of the offending packet. ICMP wasn’t really developed
for humans to interact with. The point is so that these error messages can be delivered between networked
computers automatically. But there’s also a
specific tool and two message types that are very useful to human operators. This tool is called ping. Some version of it
exists on just about every operating system and
has for a very long time. Ping is a super
simple program and the basics are the same no matter which operating
system you’re using. Ping lets you send
a special type of ICMP message called
an echo request. An ICMP echo request essentially
just as a destination. Hey, are you there? If the destination is up and running and able to
communicate on the network, it’ll send back an ICMP
echo reply message type. You can invoke the
ping command from the command line of any
modern operating system. In its most basic use, you just type ping
and a destination IP, or a fully qualified
domain name. Output of the ping
command is very similar across each of the different
operating systems. Every line of output will generally display
the address sending the ICMP echo reply and how long it took for the
round-trip communications. It will also have the
TTL remaining and how large the ICMP
message is in bytes. Once the command ends, there will also be some
statistics displayed, like percentage of packets
transmitted and received, the average round-trip time, and a couple of other
things like that. On Linux and macOS, the ping command
will run until it’s interrupted by an end user
sending an interrupt event. They do this by pressing
the Control key and the C key at the same time. On Windows, paying defaults to only sending four echo requests. In all environments, ping supports a number of command line flags that let
you change its behavior, like the number of
echo requests to send, how large they should be, and how quickly they
should be sent. Check out the documentation for your operating system to
learn a little bit more.

Tracing Your Way Through Networks with Traceroute: A Tutorial

Ever wondered how your data travels across the internet? What happens when your video call lags, or your online game experiences delay? Traceroute can be your secret weapon to investigate these mysteries! This tutorial will guide you through using Traceroute, a powerful tool to trace the path your data takes and identify potential bottlenecks or issues.

What is Traceroute?

Imagine dropping a breadcrumb trail along a winding path. Traceroute works similarly, sending packets with a limited lifespan (Time-to-Live) that get “discarded” by routers along the way, triggering messages revealing each router’s address. By piecing together these messages, you can map the complete route your data takes.

Getting Started:

1. Open your command prompt:
   • Windows: Search for “Command Prompt” and open it.
   • MacOS/Linux: Open “Terminal” from your Applications/Utilities folder.
2. Run the Traceroute command:
   • Windows: tracert [website address] (e.g., tracert google.com)
   • MacOS/Linux: traceroute [website address]
3. Interpreting the results:
   • Each line shows a “hop,” a router your data passes through.
   • You’ll see the hop number, round-trip time (in milliseconds), and the router’s IP address (and sometimes hostname).
   • Higher response times indicate potential delays or congestion.

Understanding the Output:

• The first hop: Usually your local router or gateway.
• Subsequent hops: Internet Service Providers (ISPs), backbone networks, and finally the destination server.
• Asterisks (*): Indicate packets exceeding the maximum hops, implying unreachable destinations or network issues.

Advanced Techniques:

• Using options: Both tracert and traceroute have options like specifying the number of hops or using UDP packets. Consult your system’s documentation for details.
• Visualizing the path: Online tools like “Visual Traceroute” can map the geographical path your data takes, offering a more intuitive view.

Troubleshooting with Traceroute:

• Identify bottlenecks: High response times at specific hops indicate potential congestion or overloaded routers.
• Pinpoint outages: Asterisks (*) can help identify unreachable network segments or server downtime.
• Compare paths: Run Traceroute at different times or from different locations to see if paths or performance vary.

Remember:

• Traceroute provides valuable insights, but it doesn’t diagnose the exact cause of issues.
• Additional tools and network knowledge might be needed for deeper troubleshooting.

By mastering Traceroute, you gain a powerful tool to navigate the hidden world of network paths and troubleshoot connectivity issues more effectively. Happy tracing!

Bonus Tip: Explore tools like MTR (Linux/MacOS) and Pathping (Windows) for real-time monitoring and more advanced path analysis.

With Ping, you now have a way to determine if you can
reach a certain computer from another one. You can also understand the general
quality of the connection. But communications across networks
especially across the internet usually cross lots of intermediary nodes. Sometimes, you need a way to determine
where in the long chain of router hops the problems actually are. Traceroute to the rescue. Traceroute is an awesome utility that lets
you discover the paths between two nodes, and gives you information
about each hop along the way. The way Traceroute works is through
a clever manipulation technique of the TTL Field at the IP Level. We learned earlier that the TTL Field is
decremented by one by every router that forwards the packet. When the TTL Field reaches zero,
the packet is discarded and an ICMP time-exceeded message is
sent back to the originating host. Traceroute uses the TTL Field
by first setting it to 1 for the first packet, then 2 for
the second, 3 for the third and so on. By doing this clever little action,
Traceroute makes sure that the very first packet sent will be
discarded by the first router hop. This results in an ICMP
time-exceeded message. The second packet will make
it to the second router, the third will make it to the third and
so on. This continues until the packet finally
makes it all the way to its destination. For each hop, Traceroute will
send three identical packets. Just like with Ping, the output of
a Traceroute command is pretty simple. On each line, you’ll see the number of
the hop and the round trip time for all three packets. You will also see the IP of
the device at each hop and a host name if Traceroute can resolve one. On Linux and Mac OS, Traceroute sends
UDP packets to very high port numbers. On Windows, the command has
a shortened name tracert, and defaults to using ICMP echo requests. On all platforms, Traceroute has more options than can
be specified using command line flags. Two more tools that are similar to
Traceroute are mtr on Linux and Mac OS and pathping on Windows. These two tools act as
long running trace routes. So you can better see how things
change over a period of time. Mtr works in real time and will
continually update its output with all the current aggregate data
about the Traceroute. You can compare this with pathping,
which runs for 50 seconds and then displays the final
aggregate data all at once.

Testing Network Connections at the Transport Layer: A Tutorial

Troubleshooting network issues often goes beyond checking basic connectivity with tools like ping. When applications misbehave or communication fails, delving deeper into the transport layer becomes crucial. This tutorial introduces two powerful tools – Netcat for Linux/MacOS and Test-NetConnection for Windows – to help you assess transport layer connectivity.

Understanding the Transport Layer:

Imagine data traveling on a highway. The network layer ensures packets reach their destination, while the transport layer handles reliable delivery between applications. Tools like ping operate at the network layer, but for application-specific communication, we need to look deeper.

Introducing Netcat (Linux/MacOS):

Netcat, also known as nc, is a versatile tool for network communication. Here’s how to use it for basic transport layer testing:

1. Open your terminal.
2. Run the command:nc [host] [port]
   • Replace [host] with the server address (e.g., google.com).
   • Replace [port] with the port number (e.80 for web traffic).
3. Interpret the results:
   • If successful, you’ll see a blinking cursor, indicating an open connection.
   • Type and press Enter to send data directly to the server.
   • Server response (if any) will be displayed in your terminal.
4. Checking port connectivity:
   • Use the -z flag (zero input/output): nc -z [host] [port]
   • This confirms if the port is open without data exchange.
   • Add the -v flag (verbose) for more detailed output: nc -zv [host] [port]

Exploring Test-NetConnection (Windows):

Test-NetConnection offers similar functionalities for Windows users:

1. Open your command prompt.
2. Run the command:Test-NetConnection -ComputerName [host] -Port [port]
   • Replace [host] with the server address.
   • Replace [port] with the port number.
3. Interpret the results:
   • The output displays various details like connectivity status, response time, and used protocols.
   • Similar to Netcat, use -Quiet to suppress unnecessary information.

Beyond the Basics:

Both Netcat and Test-NetConnection have extensive capabilities beyond these basic examples. Consider exploring:

• Advanced options: Netcat offers various flags for data transfer, encryption, and more. Test-NetConnection allows specifying protocols and customizing tests.
• Advanced use cases: These tools can be used for file transfers, creating simple servers, and more network-related tasks.

Remember:

• Use these tools responsibly and ethically.
• Always obtain proper permissions before testing external servers.
• Consult the respective documentation for detailed options and advanced usage.

By mastering these tools, you gain valuable insights into transport layer connectivity, empowering you to effectively troubleshoot network issues and ensure smooth application communication. Happy testing!

We’ve covered a bunch of ways to test
connectivity between machines at the network layer, but sometimes you need to know if things
are working at the transport layer. For this, there are two super
powerful tools at your disposal. Netcat on Linux and MacOS and
Test-NetConnection on Windows. The Netcat tool can be run
through the command nc and has two mandatory arguments,
a host and a port. Running nc google.com 80
would try to establish a connection on port 80 to google.com. If the connection fails,
the command will exit. If it succeeds, you’ll see a blinking
cursor waiting for more input. This is a way for you to actually send
application layer data to the listening service from your own keyboard. If you’re really only curious about
the status of a port, you can issue the command with the -z flag,
which stands for zero input output mode. The -v flag, which stands for
verbose is also useful in this scenario. This makes the command output useful
to human eyes as opposed to non verbose output, which is best for
usage and scripts. Side note,
verbose basically means talking too much. So, while I bet you want to throw
up a flag on me and my jabbering, we still have lots to get through. Okay, so by issuing the Netcat
command with the -z and -v flags, the command’s output will simply
tell you if a connection to the porting question is possible or not. On Windows, Test-NetConnection is a command with
some of the similar functionality. If you run Test-NetConnection
with only a host specified, it will default to using an ICMP echo
request, much like the program ping, but it will display way more data, including
the data link layer protocol being used. When you issue Test-NetConnection
with the dash port flag, you can ask it to test
connectivity to a specific port. It’s important to call out that both
Netcat and Test-NetConnection are way more powerful than the brief port connectivity
examples we’ve covered here. In fact, there’s such complex tools
that covering all of their functionality would be too much for one video. You should read up about all of the other
things these super powerful tools can do.

Understanding Name Resolution with nslookup: A Hands-On Tutorial

The internet might seem like magic, but behind the scenes, complex processes occur, like turning user-friendly website names into numerical IP addresses computers understand. This is where name resolution, and tools like nslookup, come in.

This tutorial equips you with the knowledge to explore and troubleshoot name resolution using nslookup, a valuable tool for IT professionals and curious minds alike.

1. What is Name Resolution?

Imagine the internet like a phone book. Websites have names (domain names), like “google.com”, but computers communicate using numbers (IP addresses), like “142.250.181.78”. Name resolution acts like a translator, converting domain names to IP addresses, enabling seamless website access.

2. Introducing nslookup:

Think of nslookup as your detective tool for name resolution. It’s a command-line utility available on Windows, Mac, and Linux, allowing you to investigate how domain names translate to IP addresses.

3. Basic Usage:

Let’s start simple. Open your terminal and type:

nslookup google.com

This displays the IP address for “google.com” and the server used for the lookup. You can use nslookup for any website!

4. Going Interactive:

For deeper dives, enter nslookup without a hostname. This starts interactive mode, where you can:

• Run multiple queries in a row: twitter.com facebook.com
• Specify the name server: server 8.8.8.8 twitter.com
• Choose record types (A for address, MX for mail exchange): set type=MX wikipedia.org

5. Advanced Troubleshooting:

Need even more details? Use set debug to see in-depth information like:

• Response packets and intermediary requests.
• Time-to-live (TTL) of cached responses.
• Serial number of the zone file used for the request.

Remember:

• set debug generates a lot of data, so use it judiciously.
• Understand the information revealed, as it might contain sensitive details.

6. Practice Makes Perfect:

Experiment with different commands and websites to solidify your understanding. Try troubleshooting simulated issues by altering DNS entries in a controlled environment.

7. Beyond the Basics:

This tutorial provides a foundation. As you progress, explore advanced features like:

• Reverse lookups (finding the domain name for an IP address).
• DNSSEC verification (ensuring data integrity).
• Customizing configuration files.

By mastering nslookup, you gain valuable insights into the internet’s inner workings and become a more informed IT professional or just a curious tech enthusiast!

Additional Resources:

• nslookup man page: https://linux.die.net/man/1/nslookup
• DNS basics: https://www.internetsociety.org/issues/past-categories/domain-name-system-dns/
• Online nslookup tool: https://mxtoolbox.com/DNSLookup.aspx

Remember, the key is to practice and explore! Happy name resolution adventures!

Name resolution is
an important part of how the Internet works. Most of the time,
your operating system handles all lookups for you. But as an IT support specialist, sometimes it can be useful
to run these queries yourself so you can see exactly what’s happening
behind the scenes. Luckily, there are lots of different command line tools out there to help you with this. The most common tool
is known as nslookup, and it’s available on all
three of the operating systems we’ve been discussing:
Linux, Mac, and Windows. A basic use of nslookup
is pretty simple. You execute the nslookup command with the host name following it, and the output displays
what server was used to perform the request
and the resolution result. Let’s say you needed to know the IP address for twitter.com, you would just enter nslookup twitter.com and the a
record would be returned. Nslookup is way more
powerful than just that. It includes an interactive
mode that lets you set additional options and run
lots of queries in a row. To start an interactive
nslookup session, you just enter nslookup without any host
name following it. You should see an angle
bracket acting as your prompt. From interactive mode, you can make lots of
requests in a row. You can also perform some extra configuration to help with more in-depth
troubleshooting. While in interactive mode, if you type server,
then an address, all the following name
resolution queries will be attempted to be made using that server instead of the
default name server. You can also enter set type equals followed by a
resource record type. By default, nslookup
will return A records, but this lets you explicitly
ask for QWERTY or MX, or even text records
associated with the host. If you really want to see
exactly what’s going on, you can enter set debug. This will allow the tool to display the full
response packets, including any
intermediary requests and all of their contents. Warning, this is a
lot of data and can contain details like
the TTL left if it’s a cached response
all the way to the serial number of the zone file the request
was made against.

DNS: Demystifying Your Options and Troubleshooting Like a Pro

Navigating the internet relies heavily on a system you might not even think about: the Domain Name System (DNS). But understanding your DNS options and troubleshooting issues can be tricky. This tutorial breaks it down for you!

1. DNS Demystified:

Think of DNS as the internet’s phone book. It translates user-friendly website names (like google.com) into numerical IP addresses computers understand. This “translation” ensures smooth access to websites and online resources.

2. Choosing Your DNS Service:

Several options exist for managing DNS resolution on your network:

• ISP-provided DNS: Most internet service providers (ISPs) offer a built-in DNS server. This is the default for most home users and often sufficient for basic needs.
• Internal DNS: Businesses often run their own DNS servers for finer control over internal host names and security.
• Public DNS: Free, publicly accessible servers like Google Public DNS (8.8.8.8) and Cloudflare DNS (1.1.1.1) offer an alternative. Use them cautiously; research their reputation and understand potential privacy implications.

3. When Things Go Wrong:

DNS issues can manifest as slow browsing, incorrect websites loading, or even complete connection failure. Here’s how to troubleshoot:

• Identify the culprit: Use ping commands to test connectivity to your primary and backup DNS servers. If pings fail, the issue might lie with them.
• Switch to a public DNS: As a temporary troubleshooting step, try changing your DNS settings to a public server like Google or Cloudflare DNS. If this resolves the issue, your primary DNS server might be the culprit.
• Consult your ISP: If the problem persists, contact your ISP for assistance. They can help diagnose and fix issues with their DNS servers.

4. Pro Tips:

• Always have a backup: Configure a secondary DNS server in case your primary one fails. This ensures uninterrupted internet access.
• Research before switching: While public DNS can be tempting, understand their data practices and potential privacy concerns before making a permanent switch.
• Beyond troubleshooting: DNS management plays a vital role in network security and performance. Consider professional help if you manage a complex network.

Remember: Choosing the right DNS service depends on your needs and priorities. While public DNS can be a helpful troubleshooting tool, prioritize your ISP’s servers for regular use and choose reputable providers if opting for public DNS. By understanding your options and using these tips, you can ensure smooth and secure DNS resolution for your internet experience.

Bonus: This tutorial provides a basic foundation. Explore further into:

• Advanced DNS record types and their uses.
• DNS security measures like DNSSEC.
• Managing and monitoring your DNS infrastructure for optimal performance.

With a little DNS knowledge, you can become a more informed internet user and troubleshoot issues like a pro!

Having functional DNS
is an important part of a functional
network in ISP almost always gives you access to a recursive name server as part of the service it provides. In most cases, these name
servers are all you really need for your computer to communicate with other
devices on the Internet. But most businesses also
run their own DNS servers. In the very least,
this is needed to resolve names
of internal hosts. Anything from naming and
computer, nais-laptop, to being able to
refer to a printer by a name instead of an IP
requires your own name server. A third option is to use a
DNS as a service provider. It’s getting more
and more popular. No matter what DNS service model you’re using on your network, it’s useful to
have a way to test DNS functionality in case you suspect something
isn’t working right. It can also be super
useful to have a backup DNS option in case you experienced
problems with your own. You might even be in the
early stages of building out a new network and even if you plan to have your
own name server, eventually, it may
not be ready for use. Some internet organizations run what are called
public DNS servers, which are name
servers specifically set up so that anyone
can use them for free. Using these public DNS servers
is a handy technique for troubleshooting any name
resolution problems you might be experiencing. Some people just use these name servers for all
their resolution needs. For a long time, public DNS servers were a tribal knowledge passed down from one sysadmin to another. In ancient sysadmin lore, it’s said that for many years the most commonly used
public DNS servers, were those run by Level
3 communications. One of the largest
ISPs in the world. Level 3 is in fact so large. They mostly do business by selling connectivity
to their network, to other ISPs that actually
deal with consumers, instead of dealing with
end-users themselves. The IP addresses for Level
3’s public DNS servers are 4.2.2.1 through 4.2.2.6. These IPs are easy to remember, but they’ve always been
shrouded in a bit of a mystery. While they’ve been available
for use by the public for almost 20 years now,
it’s not a service. Level 3 officially has ever acknowledged or advertised, why? We might never know. It’s one of the great mysteries of our
ancient sysadmin lore. Anyway, other easy to remember options are the IPs for
Google’s public DNS. Google operates public
name servers on the IPs, 8.8.8.8, and 8.8.4.4. Unlike the Level 3 IPs, these are efficiently
acknowledged and documented by Google to be
used for free by anyone. Most public DNS servers are available globally
through anycast. Lots of other organizations also provide public DNS servers, but few are as easy to
remember as those two options. Always do your research
before configuring any of your devices to use
that type of name server. Hijacking outbound
DNS requests with faulty responses
is an easy way to redirect your users
to malicious sites. Always makes sure
the name server is run by a reputable
company and try to use the name servers provided by your ISP outside of
troubleshooting scenarios. Most public DNS servers also respond to ICMP echo request, so there are a great
choice for testing general Internet
connectivity using ping.

Refresher time. Remember
that DNS is a global system managed in a tiered hierarchy with ICANN at the top level. Domain names need to be globally unique for a global
system like this to work. You can’t just have
anyone decide to use any domain name,
it’d be chaos. Enter the idea of a registrar, an organization
responsible for assigning individual domain names to other organizations
or individuals. Originally, there were
only a few registrars. The most notable was a company named
Network Solutions Inc. It was responsible for
the registration of almost all domains that
weren’t country-specific. As the popularity of
the internet grew, there was eventually
enough market demand for competition in this space. Finally, the United States government and
Network Solutions, Inc came to an agreement to let other companies also
sell domain names. Today, there are hundreds of companies like this
all over the world. Registering a domain name
for use is pretty simple. Basically, you create an
account with the registrar, use their web UI to search for a domain name to determine
if it’s still available, then you agree upon a price to pay and the length of
your registration. Once you own the domain name, you can either have the
registrar’s name servers act as the authoritative
name servers for the domain, or you can configure your own servers to
be authoritative. Domain names can also
be transferred by one party to another and from
one registrar to another. The way this usually
works is that the recipient registrar will
generate a unique string of characters to prove that you own the domain and that you’re allowed to transfer
it to someone else. You’d configure your
DNS settings to contain this string
in a specific record, usually a text record. Once this information
has propagated, it can be confirmed
that you both own the domain and
approve its transfer. After that, ownership would move to the new
owner or registrar. An important part of the domain
name registration is that these registrations only exist for a fixed amount of time. You typically pay to register domain names for a
certain number of years. It’s important to
keep on top of when your domain names might
expire because once they do, they’re up for grabs and anyone
else could register them.

Hosts Files: A Beginner’s Guide to the Old-School Network Address Book

Ever wondered how computers translated friendly names like “web server” into numerical addresses before fancy DNS existed? Look no further than the hosts file, a simple yet powerful tool still found in your devices today!

Part 1: A Trip Back in Time:

Imagine a pre-DNS world where remembering strings of numbers was the norm. Hosts files offered a solution, acting as a personal phone book for your network. Each line mapped an IP address to a descriptive name, making life easier. For example:

1.2.3.4 web server
10.0.0.1 internal-printer

With these entries, you could type “web server” in your browser or ping it, and your computer would understand, thanks to the magic of the hosts file.

Part 2: The Present Day – Not Just a Relic:

While DNS reigns supreme, hosts files haven’t vanished entirely. Here’s why they’re still relevant:

• Loopback love: Every device uses the loopback address (127.0.0.1) to talk to itself. Guess what defines it? Yep, a hosts file entry (usually 127.0.0.1 localhost).
• Troubleshooting hero: Need to test a website without relying on DNS? Force your computer to think a specific domain points to a particular IP by editing your hosts file (carefully, of course!).
• Customization corner: Some software might require specific hosts file entries to function properly.

Part 3: A Word of Caution (and Alternatives):

While hosts files offer some benefits, remember:

• Security concerns: Malware can exploit hosts files for malicious redirects. Stick to trusted sources for any manual edits.
• Limited scope: Hosts files only affect the individual device they’re on, not a network-wide solution.
• Modern marvel: DNS is generally more secure and efficient for resolving domain names. Use it as your primary tool.

Bonus Tip: Most major operating systems let you edit your hosts file. However, proceed with caution and remember to back it up before making changes!

Part 4: Beyond the Basics:

Ready to delve deeper? Explore:

• Different hosts file locations on various operating systems.
• Advanced troubleshooting techniques using hosts files.
• The security implications of editing hosts files responsibly.

By understanding hosts files, you gain valuable insights into network history and discover a handy troubleshooting tool, all while appreciating the power and convenience of modern DNS. Remember, knowledge is power, use it wisely!

Long before DNS wasn’t established and globally
available technology, it was clear to computer
operators that they needed a language-based system to
refer to network devices. We’ve talked about how
humans are way better at remembering descriptive
words, than numbers. But numbers represent
the natural way that computers think
and communicate. The original way that numbered
network addresses were correlated with words
was through hosts files. A host file is a flat
file that contains on each line a network address followed by the host name
it can be referred to as. For example, a line
in a host file might read 1.2.3.4 web server. This means that on the computer where this
host file resides, a user could just
refer to web server instead of the IP 1.2.3.4. Hosts files are evaluated by the networking stack of the
operating system itself. That means the presence of an
entry there would translate to anywhere you might refer
to a networking address. Sticking with our
earlier example, a user could type web server
into a web browser URL bar, or could issue a ping web
server command and it would get translated to
1.2.3.4 in either case. Hosts files might be
ancient technology, but they’ve stuck
around all this time. All modern operating systems, including those that power
our phones and tablets, still have hosts files. One reason is because
of a special IP address we haven’t covered yet:
the loopback address. A loopback address
always points to itself. A loopback address is a way of sending network
traffic to yourself. Sending traffic to a
loopback address bypasses all network
infrastructure itself and traffic like that
never leaves the node. The loopback IP, for
IPv4 is 127.0.0.1, and it’s still to this
day configured on every modern operating system through an entry in a host file, almost every host file in existence will in the
very least contain a line that reads
127.0.0.1 localhost, most likely followed
by::1 localhost, where::1 is the loopback
address for IPv6. Since DNS is everywhere, host files aren’t
used much anymore, but they still exist and they’re still
important to know about. Some software even require
specific entries in the host file to
operate properly as antiquated as this
practice may seem. Finally, host files
are a popular way for computer viruses to disrupt
and redirect users’ traffic. It’s not a great idea to
use host files today, but they do have some useful
troubleshooting purposes that can be helpful
in IT support. Host files are examined before a DNS resolution attempt occurs on just about every
major operating system. This lets you force an
individual computer to think a certain domain name always
points at a specific IP. Got it. We’ve covered a lot, so take time to go
back if you need to and make sure you understand the concepts
we’re discussing.

You’ve probably been
hearing people talk about the Cloud more and more. There are public Clouds
and private Clouds and hybrid Clouds
and rain Clouds, but those aren’t
really relevant here. There are Cloud clients and Cloud storage and
Cloud servers too. You might hear the
Cloud mentioned in newspaper headlines
and TV advertisements. The Cloud is the
future, so we’re told. IT support specialists
really need to keep up on the latest innovations in tech in order to support them. But what exactly is the Cloud? The truth is the Cloud isn’t a single technology or invention or anything
tangible at all. It’s just a concept and to
throw in another Cloud joke, a pretty nebulous one at that. The fact that the term, the Cloud has been applied to something so difficult to
define is pretty fitting. Basically, Cloud computing is a technological
approach where computing resources
are provisioned in a sharable way so that lots of users get what they
need when they need it. It’s an approach that leans heavily on the idea
that companies provide services for each other using these
shared resources. At the heart of
Cloud computing is a technology known as
hardware virtualization. Hardware virtualization
is a core concept of how Cloud computing
technologies work. It allows the concept of
a physical machine and a logical machine to be
abstracted away from each other. With virtualization, a single
physical machine called a host could run many individual virtual
instances called guests. An operating system
expects to be able to communicate with the underlying
hardware in certain ways. Hardware virtualization
platforms employ what’s called a hypervisor. A hypervisor is a
piece of software that runs and manages
virtual machines while also offering these guests a virtual operating platform that’s indistinguishable
from actual hardware. With virtualization, a
single physical computer can act as the host for many independent
virtual instances. They each run their own
independent operating system, and in many ways are
indistinguishable from the same operating systems
running on physical hardware. The Cloud takes this
concept one step further. If you build a huge cluster of interconnected
machines that can all function as hosts for
lots of virtual guests, you’ve got a system
that lets you share resources among all
of those instances. Let’s try explaining this
in a more practical way. Let’s say you have the
need for four servers. First, you need an email server. You’ve carefully analyzed
things and expect this machine will need eight gigs of
RAM to function properly. Next, you need a name server. The name server barely
needs any resources since it doesn’t have to perform anything
really computational. But you can’t run it on the same physical machine
as your email server since your email server
needs to run on Windows and your name server
needs to run on Linux. Now, the smallest
server configuration your hardware vendor sells is a machine with eight
gigabytes of RAM, so you have to buy another one
with those specifications. Finally, you have a
financial database. This database is
normally pretty quiet and doesn’t need
too many resources during normal operations. But for your end of month billing processes to
complete in a timely manner, you determine the machine would
need 32 gigabytes of RAM. It has to run on a
special version of Linux designed just
for the database, so the name server can’t
also run on this machine. You order a server
with that much RAM and then a second with the same specifications to
act as a backup. In order to run your
business this way, you have to purchase
four machines with a grand total of 80
gigabytes of RAM. That seems pretty outrageous, since it’s likely that
only 40 gigabytes of this total RAM will ever
be used at one time. Most of the month
you’re using much less. That’s a lot of
money to spend on resources you’re either never
going to use or rarely use. Let’s forget about that model. Instead, let’s imagine
a huge collection of interconnected servers that
can host virtualized servers. These virtual instances
running on this collection of servers can be given access to the underlying
RAM as they need it. Under this model,
the company that runs the collection of
servers can charge you to host virtual instances of your servers instead
of you buying the four physical machines
and it could cost much less than what you’d spend on the four
physical servers. The benefits of the
Cloud are obvious, but let’s take it
a step further. The Cloud computing
company that can host your virtualized instances also offer dozens of other services. Instead of worrying about setting up your own
backup solution, you can just employ theirs. It’s easy. If you
need a load balancer, you can just use their solution. Plus, if any underlying
hardware breaks, they just move your
virtual instance to another machine without
you even noticing. To top it all off,
since these are all virtual servers
and services, you don’t have to
wait for the physical hardware you order to show up, you just need to click a few
buttons in a web browser. That’s a pretty good deal. In our analogy, we used an example of what
a public Cloud is, a large cluster of machines
run by another company. A private Cloud takes
the same concepts, but instead it’s
entirely used by a single large corporation and generally physically hosted
on its own premises. Another term you might run into, a hybrid Cloud, isn’t really a separate concept, it’s just a term used to describe situations where
companies might run things like their most sensitive proprietary technologies on a private Cloud while entrusting their less sensitive
servers to a public Cloud. Those are the basics
of what the Cloud is. It’s a new model in computing
where large clusters of machines let us use the total resources
available in a better way. The Cloud lets you provision a new server in a
matter of moments and leverage lots of existing services instead of
having to build your own. To sum up, it’s blue skies ahead for anyone
using the Cloud. Sorry, I couldn’t resist.

Cloud Beyond Infrastructure: A Comprehensive Guide to XaaS

The cloud journey doesn’t stop at renting virtual machines. Dive deeper into the diverse world of XaaS, where “X” stands for “Anything,” unlocking a vast spectrum of services beyond infrastructure. This tutorial empowers you to understand and leverage XaaS models for your business needs.

XaaS: More Than Bricks and Mortar:

Imagine the cloud not just as servers in the sky, but as a complete service ecosystem. XaaS encompasses various service models, each catering to specific needs:

• Infrastructure as a Service (IaaS): The foundation, providing virtual machines, storage, and networking like building blocks. Think Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP).
• Platform as a Service (PaaS): Your application development playground, offering pre-built platforms with tools and resources to build and deploy applications easily. Heroku, Cloud Foundry, and AWS Elastic Beanstalk are prime examples.
• Software as a Service (SaaS): The ready-to-use applications, eliminating installation and maintenance hassles. Popular SaaS options include Gmail, Salesforce, Dropbox, and Adobe Creative Cloud.

Understanding the Nuances:

Each XaaS model caters to different stages of your cloud journey:

• IaaS: Perfect for companies with granular control needs and technical expertise.
• PaaS: Ideal for rapid application development and deployment, without managing underlying infrastructure.
• SaaS: Best for off-the-shelf solutions, reducing IT overhead and simplifying user access.

Benefits of XaaS:

• Cost-effectiveness: Pay only for what you use, avoiding upfront infrastructure investments and ongoing maintenance costs.
• Scalability: Seamlessly adjust your resource usage as your business grows or shrinks.
• Accessibility: Work from anywhere, anytime, with just an internet connection.
• Security: Leverage the robust security measures implemented by cloud providers.
• Agility: Focus on core business objectives, leaving infrastructure and software management to the experts.

Choosing the Right XaaS Model:

Consider these factors when making your choice:

• Technical expertise: Do you have an in-house IT team for IaaS management, or prefer a more hands-off approach with PaaS/SaaS?
• Application needs: Do you require customizability (PaaS) or pre-built solutions (SaaS)?
• Budget: Evaluate upfront costs versus ongoing subscription fees for different models.

The XaaS Landscape:

Beyond IaaS, PaaS, and SaaS, the XaaS world expands to niche offerings like:

• Database as a Service (DaaS): Managed database solutions like Amazon RDS and Azure SQL Database.
• Security as a Service (SECaaS): Cloud-based security solutions for threat detection and prevention.
• Analytics as a Service (AaaS): Data analytics platforms accessible on-demand.

The Future of XaaS:

As cloud adoption accelerates, XaaS models will continue to evolve, offering greater flexibility, specialization, and innovation. Businesses can tailor their cloud strategy to unique needs, optimizing costs, agility, and efficiency.

Remember:

• Understanding XaaS models empowers informed decision-making for your cloud journey.
• Choosing the right model depends on your specific technical expertise, application needs, and budget.
• XaaS opens a world of possibilities beyond traditional infrastructure, enabling businesses to focus on their core values and achieve greater success.

Start exploring the XaaS landscape today and unlock the full potential of the cloud!

In our last video, we gave you a basic
definition of what cloud computing is, but the term has really come to mean so much
more than just hosting virtual machines. Another term that’s been used more and more with the rise of cloud
computing is X as a service. Here, the X can stand for
lots of different things. The way we’ve described the clouds so far, would probably best be defined as
infrastructure as a service or IaaS. The idea behind infrastructure as
a service is that you shouldn’t have to worry about building your own network or
your own servers. You just pay someone else to
provide you with that service. Recently, we’ve seen the definition
of the cloud expand well beyond infrastructure as a service. The most common of these
are platform as a service or PaaS, and software as a service or SaaS. Platform as a service is a subset of cloud
computing where a platform is provided for customers to run their services. This basically means that
an execution engine is provided for whatever software someone wants to run. A web developer writing a new application
doesn’t really need an entire server, complete with a complex file system,
dedicated resources and all those other things. It doesn’t matter if this
server is virtual or not, they really just need an environment
that their web app can run in, that is what platform
as a service provides. Software as a service takes
this one step further, infrastructure as a service abstracts away
the physical infrastructure you need, and platform as a service abstracts
away the server instances you need. Software as a service is essentially
a way of licensing the use of software to others while keeping that software
essentially hosted and managed. Software as a service has become
really popular for certain things. A great example is email, offerings like
Gmail for business from Google or Office 365 Outlook from Microsoft are really
good examples of software as a service. Using one of those services
means you’re trusting Google or Microsoft to handle just about
everything about your email service. Software as a service is a model
that’s gaining a ton of traction. Web browsers have become so feature
packed that lots of things that required standalone software in the past can
now run well inside of a browser. And if you can run something in a browser,
it’s a prime candidate for SaaS today. You can find everything from word
processors to graphic design programs, to human resource management
solutions offered under a subscription based SaaS model. More and more, the point of a business’s
network is just to provide an internet connection to access different software or
data in the cloud.

Cloud Storage: Unleash the Power of Your Data

Data is the lifeblood of our digital world, and cloud storage has revolutionized how we store, access, and manage it. This tutorial empowers you to understand the benefits of cloud storage and harness its potential for personal or business needs.

What is Cloud Storage?

Imagine a vast digital warehouse accessible from anywhere, anytime. That’s cloud storage! You entrust your data (documents, photos, videos, etc.) to a cloud provider who securely stores it in their data centers. Access it seamlessly through any device with an internet connection, eliminating physical storage limitations.

Why Choose Cloud Storage?

Traditional storage comes with hassles: managing hardware, worrying about backups, and limited accessibility. Cloud storage offers a refreshing alternative:

• Convenience: Access your data from anywhere, anytime, on any device. No more lugging around external drives!
• Security: Cloud providers invest heavily in robust security measures, offering better protection than most personal setups.
• Scalability: Need more storage? No problem! Simply upgrade your plan without worrying about physical limitations.
• Cost-effectiveness: Pay only for the storage you use, making it ideal for both individuals and businesses.
• Automatic Backups: Never lose precious memories or work again. Cloud storage can automatically back up your data, ensuring constant protection.

Getting Started with Cloud Storage:

1. Choose a Provider: Research and compare popular options like Google Drive, Dropbox, Amazon S3, and Microsoft OneDrive. Consider factors like storage space, security features, and pricing plans.
2. Upload Your Data: Use the provider’s web interface or desktop app to upload your files. Some offer automatic syncing, keeping your local and cloud copies in sync.
3. Organize and Share: Create folders, share files with others, and collaborate seamlessly. Enjoy the freedom of accessing and managing your data from any device.

Advanced Features:

• Version Control: Recover previous versions of files in case of accidental edits.
• File Sharing: Set access permissions and collaborate with teams in real-time.
• Integration with Apps: Utilize various cloud-based apps that directly access your stored data.
• Security Features: Enable two-factor authentication and encryption for enhanced protection.

Cloud Storage Beyond Personal Use:

Businesses leverage cloud storage for:

• Data Backups: Securely store critical business data and ensure disaster recovery.
• File Sharing and Collaboration: Facilitate teamwork and information sharing within and across teams.
• Scalability and Cost Management: Adapt storage needs dynamically and pay only for what you use.
• Accessibility: Empower employees to access company data from anywhere, boosting productivity.

Remember:

• Security: Choose a reputable provider with strong security practices.
• Privacy: Understand the provider’s data privacy policies and terms of service.
• Compliance: Ensure chosen solutions comply with any relevant industry regulations.

Embrace the Cloud Storage Revolution:

Cloud storage offers a convenient, secure, and scalable solution for managing your data in today’s world. Explore different options, understand the benefits, and unlock the full potential of your digital assets!

Another popular way to use Cloud technologies
is Cloud storage. In a Cloud storage system, a customer contracts a
cloud storage provider to keep their data secure,
accessible, and available. This data could be anything from individual documents to
large database backups. There are lots of benefits of Cloud storage over a
traditional storage mechanism. Without Cloud storage, there’s the general headache
of managing a storage array. Hard drives are one of the most frequent
components that may experience a malfunction
in a computer system. That means that you’d have to carefully monitor the devices being used for storage and
replace parts when needed. By using a Cloud
storage solution, it’s up to the
provider to keep the underlying physical
hardware running. Also, Cloud storage
providers usually operate in lots of different
geographic regions. This lets you easily duplicate your data across multiple sites. Many of these providers
are even global in scale, which lets you make
your data more readily available for users
all over the world. It also provides protection
against data loss since if one region of
storage experiences problems, you can probably still access your data in a different region. Cloud storage solutions
also grow with you. Typically, you’ll pay for exactly how much
storage you’re using instead of having a fixed amount like you would with
local storage. While this doesn’t
always mean that Cloud storage is necessarily
a cheaper option, it does mean that you
can better manage what your expenses for
storage actually are. Not only is Cloud
storage useful for replacing large-scale
local storage arrays, it’s also a good solution for backing up smaller bits of data. Your smartphone might
automatically upload every picture you take to
a Cloud storage solution. If your phone dies, you lose it, or accidentally delete pictures, they’re still there waiting
for you in the Cloud. That way, you’ll never lose those precious photos
of your pooch Tako.

Understanding the Shift: From IPv4 to IPv6

The internet’s growth has been phenomenal, and our trusty IPv4 addressing system is struggling to keep up. Enter IPv6, the next-generation protocol designed to address this limitation.

This tutorial guides you through the key differences between IPv4 and IPv6, highlighting the need for the upgrade and its benefits.

Why the Shift?

Imagine having only 4.2 billion unique addresses for the ever-growing number of devices connecting to the internet. That’s the reality with IPv4, a 32-bit addressing system reaching its saturation point. IPv6, with its 128-bit addresses, offers an astronomical increase – an “undecillion” times more addresses!

Key Differences:

• Address Size: IPv4 uses 4 octets (32 bits) of decimal numbers, while IPv6 utilizes 8 groups of 4 hexadecimal digits (128 bits).
• Notation: IPv4 addresses are written as four decimal numbers separated by dots (e.g., 192.168.1.1). IPv6 uses eight groups of four hexadecimal digits separated by colons (e.g., 2001:0db8:85a3:0000:0000:abcd:0001:0002).
• Subnetting: Both use CIDR notation, but applied to the network ID portion in IPv6 addresses.

Benefits of IPv6:

• Vastly Larger Address Space: No more worrying about address exhaustion for the foreseeable future.
• Simpler Network Management: Clearer distinction between network and host IDs within the address itself.
• Enhanced Security: Built-in security features like IPsec for better protection.
• Improved Mobility: Seamless connectivity across different network types.

IPv6 Adoption:

While not yet dominant, IPv6 adoption is steadily increasing. Many devices and networks now support it, and the transition is crucial for the internet’s future growth.

Ready to Embrace IPv6?

Understanding the limitations of IPv4 and the advantages of IPv6 is essential for anyone involved in networking or technology. Familiarize yourself with the concepts, explore compatible devices and services, and contribute to a more robust and sustainable internet infrastructure.

Beyond the Basics:

• Explore online resources for deeper dives into IPv6 addressing, configuration, and implementation.
• Consider getting certified in IPv6 networking to advance your professional skills.
• Encourage the use of IPv6-compatible devices and services whenever possible.

Remember, the shift to IPv6 is not just an upgrade; it’s a necessity for a growing and evolving digital world. Take the first step towards understanding and embracing this essential change!

Time for some real talk. Here’s the hard truth. The IANA is out of IP addresses. When IPv4 was first developed, a 32-bit number was chosen to represent the address
for a node on a network. The Internet was in its
infancy and no one really expected it to explode in
popularity the way it has. Thirty-two bits were chosen, but it’s just not enough
space for the number of Internet-connected devices
we have in the world. IPv6 was developed exactly
because of this issue. By the mid-1990s, it was more and more obvious
that we were going to run out of IPv4 address
space at some point, so a new Internet
Protocol was developed. Internet Protocol
version 6 or IPv6. You might wonder what happened
to version 5 or IPv5. It’s actually a
fun bit of trivia. IPv5 was an
experimental protocol that introduced the
concept of connections. It never really
saw wide adoption and connection state was handled better later on by the
transport layer and TCP. Even though IPv5 is mostly
a relic of history, when development
of IPv6 started, the consensus was to not
reuse the IPv5 name. The biggest difference
between IPv4 and IPv6 is the number of bits
reserved for an address. While IPv4 addresses
are 32 bits, meaning there can be around 4.2 billion
individual addresses, IPv6 addresses are
128 bits in size. The size difference is
staggering once you do the math. Don’t worry, we won’t make you. Two to the power of 128 would produce a 39-digit long number. That number range has a
name you’ve probably never even heard of, an undecillion. An undecillion isn’t
a number you hear a lot because it’s ginormous, there really aren’t things
that exists at that scale. Some guesses on the total
number of atoms that make up the entire planet earth and every single thing on it
get into that number range. That should tell you
we’re talking about a very large number. If we can give every atom on
Earth its own IP address, we’ll probably be okay when it comes to network devices
for a very long time. Just for fun, let’s look at what that number actually looks like. It looks like this.
Wow, mind-blowing. Just like how an IPv4 address is really just a 32-bit
binary number, IPv6 addresses are really
just 128-bit binary numbers. IPv4 addresses are written
out in four octets of decimal numbers just to make them a little more
readable for humans. But trying to do the same for an IPv6 address
just wouldn’t work. Instead, IPv6
addresses are usually written out as eight
groups of 16 bits each. Each one of these
groups is further made up of four hexadecimal numbers. A full IPv6 address might
look something like this. That’s still way too long, so IPv6 has a notation method that lets us break
that down even more. A way to show how
many IPv6 addresses there are is by looking
at our example IP. Every single IPv6
address that begins with 2001:0db8 has been reserved for documentation and education or for books and courses
just like this one. That’s over 18
quintillion addresses, much larger than the
entire IPv4 address space reserved just
for this purpose. There are two rules
when it comes to shortening an IPv6 address. The first is that you can remove any leading zeros from a group. The second is that any
number of consecutive groups composed of just zeros can
be replaced with two colons. I should call out that
this can only happen once for any specific address. Otherwise, you couldn’t know exactly how many zeros were replaced by
the double colons. For this IP, we could apply the first rule and remove all leading zeros
from each group. This would leave us with this. Once we apply the second rule, which is to replace
consecutive sections containing just zeros
with two colons, we’ll end up with this. This still isn’t as readable
as an IPv4 address, but it’s a good
system that helps reduce the length a little bit. We can see this
approach taken to the extreme with IPv6
loopback address. You might remember
that with IPv4, this address is 127.0.0.1. With IPv6, the loopback address is 31 zeros with
a one at the end, which can be condensed all
the way down to just::1. The IPv6 address space has several other
reserved address ranges besides just the
one reserved for documentation purposes
or the loopback address. For example, any address
that begins with FF00: : is used for multi-cast, which is a way of addressing
groups of hosts all at once. It’s also good to know that
addresses beginning with FE80:: are used for
link-local unicast. Link-local unicast
addresses allow for local network segment
communications and are configured based upon
a host’s MAC address. The link-local
address are used by an IPv6 host to receive
their network configuration, which is a lot like
how DHCP works. The host’s MAC address is
run through an algorithm to turn it from a 48-bit number
into a unique 64-bit number. It’s then inserted into
the address’s host ID. The IPv6 address
space is so huge, there was never any need to
think about splitting it up into address classes like
we used to do with IPv4. From the very beginning, an IPv6 address had a very simple line between
network ID and host ID. The first 64 bits of any IPv6
address is the network ID, and the second 64 bits of any IPv6 address is the host ID. This means that any
given IPv6 network has space for over nine
quintillion hosts. Still, sometimes network
engineers might want to split up their network for
administrative purposes. IPv6 subnetting uses
the same cider notation that you’re already
familiar with. This is used to define
a sub-net mask against the network ID portion
of an IPv6 address.

Decoding the Power of IPv6: Diving into the Simpler and More Flexible Header

The internet’s evolution demands efficient infrastructure, and the IPv6 protocol rises to the challenge with its streamlined yet powerful header. This tutorial unlocks the key features of the IPv6 header, highlighting its advantages over its predecessor, IPv4.

Farewell Complexity, Hello Efficiency:

One of the most striking improvements in IPv6 is the header itself. Compared to IPv4’s bulky structure, IPv6 adopts a minimalist approach, boasting fewer fields and a shorter overall length. This translates to faster transmission across networks, minimizing delays and enhancing performance.

Prioritizing Traffic Flow:

IPv6 prioritizes the smooth flow of diverse traffic types. Unlike IPv4, it introduces two dedicated fields:

• Traffic class: Categorizes traffic based on its nature (e.g., real-time, mission-critical, background), allowing routers to assign appropriate priorities.
• Flow label: Works in conjunction with the traffic class to further refine quality-of-service (QoS) for specific data streams.

Flexibility through Optional Headers:

The true genius of the IPv6 header lies in its ability to handle diverse network configurations without sacrificing efficiency. It achieves this through the innovative “next header” field:

• This field indicates the type of optional header that follows the main header, if any.
• These optional headers cater to specific functionalities like security, mobility, and fragmentation, offering granular control without cluttering the core header.
• This modular design allows for flexible network setups while maintaining a lightweight structure.

Addressing the Future:

With its 128-bit address space, IPv6 dwarfs the limitations of IPv4’s 32-bit addresses. This vast addressing pool ensures we won’t run out of unique identifiers anytime soon, future-proofing the internet’s growth.

Ready to Embrace the Future of Networking?

Understanding the IPv6 header empowers you to appreciate its efficiency, flexibility, and scalability. As the internet continues to evolve, IPv6 stands as the cornerstone of a robust and adaptable network infrastructure. Explore further resources to delve deeper into specific header fields, optional headers, and practical applications of IPv6. Remember, embracing this future-proof technology empowers you to contribute to a thriving and connected digital world.

Additional Resources:

• Interactive visualization of the IPv6 header: https://www.youtube.com/watch?v=KTSZ7gK4IXk
• Detailed explanation of optional headers: https://www.icann.org/resources/pages/ipv6-initiative-2017-02-28-en
• IPv6 implementation guides and tutorials: https://www.internetsociety.org/wp-content/uploads/2017/09/ISOC-PolicyBrief-IPv6-20160419-en.pdf

Start your journey towards understanding IPv6 today and pave the way for a brighter, more connected future!

When IPv6 was being developed, they took
the time to introduce a few improvements instead of just figuring out a way
to increase the address size, this should come as a relief to you and IT support specialists love
networks that perform well. One of the most elegant improvements
was made to the IPv6 header which is much simpler than the IPv4-1. The first field in an IPv6
header is the version field. This is a 4-bit field that defines
what version of IP is in use. You might remember that an IPv4 header
begins with this exact same field. The next field is called
the traffic class field. This is an 8-bit field that defines the
type of traffic contained within the IP datagram and allows for different classes of traffic to
receive different priorities. The next field is the flow label field. This is a 20-bit field that’s used in
conjunction with the traffic class field for routers to make decisions
about the quality of service level for a specific datagram. Next, you have the payload length field. This is a 16-bit field that
defines how long the data payload section of the datagram is,
then you have the next header field. This is a unique concept to IPv6 and
needs a little extra explanation. IPv6 addresses are four times
as long as IPv4 addresses. That means they have more ones and zeros which means that they take
longer to transmit across a link. To help reduce the problems with
additional data that IPv6 addresses impose on the network, the IPv6 header was
built to be as short as possible. One way to do that is to take
all of the optional fields and abstract them away from
the IPv6 header itself. The next header field defines what kind
of header is immediately after this current one. These additional headers are optional,
so they’re not required for a complete IPv6 datagram. Each of these additional optional headers
contain a next header field and allow for a chain of headers to be formed if
there’s a lot of optional configuration. Next we have what’s called
the hop limit field. This is an 8-bit field
that’s identical and purpose to the TTL field
in an IPv4 header. Finally, we have the source and destination address fields
which are each 128 bits. If the next header field specified another
header, it would follow at this time. If not, a data payload, the same length as specified in
the payload length field would follow.

Navigating the Bridge: IPv6 and IPv4 Coexistence

The internet’s journey to IPv6, with its vast address space and enhanced security, requires a smooth coexistence with the established IPv4. This tutorial explores the key mechanisms enabling this cohabitation, paving the way for a seamless transition.

Challenges of Simultaneous Adoption:

Switching an entire internet infrastructure overnight is impractical. Countless devices lack IPv6 capabilities, necessitating a bridge between the two protocols.

The Art of Address Mapping:

• IPv4-mapped address space: Dedicated IPv6 addresses with specific prefixes (80 zeros followed by 16 ones) directly map to IPv4 counterparts. This allows IPv4 traffic to seamlessly navigate an IPv6 network.

Tunneling Through the Old Paths:

• IPv6 tunnels: Imagine data packets traveling in protective tubes. IPv6 tunnels encapsulate IPv6 data within traditional IPv4 packets, enabling travel across IPv4 networks.
• Tunnel servers: Specialized servers at tunnel endpoints handle the encapsulation and decapsulation of data packets, ensuring smooth transmission.
• Tunnel brokers: Companies offer tunnel broker services, eliminating the need for dedicated servers for smaller organizations.

A Multitude of Paths, One Destination:

Several competing tunnel protocols exist (SIT, GRE, etc.), each with its advantages. The dominant technology is still evolving. Ultimately, the chosen protocol matters less than the overarching goal: a smooth transition.

The Vision of a Tunnelless Future:

Tunneling serves as a temporary bridge, paving the way for IPv6’s ultimate dominance. The future envisions an internet built entirely on IPv6, eliminating the need for tunnels and their limitations.

Join the Transition Journey:

By understanding these coexistence mechanisms, you become an active participant in shaping the future of the internet. Embrace ongoing learning, explore resources, and contribute to a robust and secure online world.

Additional Resources:

• Interactive visualization of IPv4-mapped addresses: https://tools.ietf.org/html/rfc4291: https://tools.ietf.org/html/rfc4291
• Detailed comparison of tunnel protocols: <invalid URL removed>: <invalid URL removed>
• Live IPv6 adoption statistics: <invalid URL removed>: <invalid URL removed>

Remember, understanding these concepts empowers you to contribute to a thriving and connected future for the internet!

It’s just not possible for
the entire Internet and all connected networks to
switch to IPv6 all at once. There’ll be way too much
coordination at play. Too many old devices that
might not even know how to speak IPv6 at all still
requiring connections. The only way IPv6 will ever take hold is to
develop a way for IPv6 and IPv4 traffic to
co-exist at the same time. This would let
individual organizations make the transition
when they can. One example of how this
can work is with what’s known as IPv4-mapped
address space. The IPv6 specifications
have set aside a number of addresses that can be directly correlated to an IPv4 address. Any IPv6 address
that begins with 80 zeros and is then
followed by 16 ones, is understood to be part of the IPv4-mapped address space. The remaining 32 bits
of the IPv6 address is just the same 32 bits of the IPv4 address it’s
meant to represent. This gives us a way for IPv4 traffic to travel
over an IPv6 network. But probably more
important is for IPv6 traffic to have a way to
travel over IPv4 networks. It’s easier for an
individual organization to make the move to IPv6 than it is for the networks at the core
of the Internet too. While IPv6 adoption
becomes more widespread, it will need a way
to travel over the old IPv4 remnants of
the Internet backbone. The primary way this is achieved today is through IPv6 tunnels. IPv6 tunnels are
conceptually pretty simple. They consist of IPv6
tunnels servers on either end of a connection. These IPv6 tunnels servers take incoming IPv6 traffic
and encapsulate it within traditional
IPv4 datagrams. This is then delivered across
the IPv4 Internet space, where it’s received by
another IPv6 tunnel server. That server performs
the D encapsulation and passes the IPv6 traffic
further along the network. Along with IPv6
tunnel technologies, the concept of an IPv6 tunnel
broker has also emerged. These are companies that provide IPv6 tunneling
endpoints for you, so you don’t have to introduce additional equipment
to your network. There are a lot of
competing protocols to be used for these IPv6 tunnels. Since this is still a
new and evolving space, it’s not clear who
the winner will be. It doesn’t really matter which tunneling technology ends up becoming the most
common solution. It will probably fade
away in time itself. The future of networking
is the adoption of IPv6 as the main protocol
at the network layer. One day we won’t need
any tunnels at all. The future is limitless and tunnelless or
something like that. You’ve done an amazing job getting through all
this information, so take some time to pat
yourself on the back.

Hi, I’m Rob. I’m Candice. Congrats on making it
through this course. Now that you’ve
made it this far, we’re here to give you a sneak peek into
what an interview on the technical subjects covered by this course might look like. We hope this will help
you have a better idea what to expect in
your next interview. Just remember to keep
learning and keep practicing. For this scenario,
let’s say that you’re working help desk for
a global company. You get a call first thing in the morning from a user
in a remote office, they sound panicked and they
tell you that the network is down in their office.
What do you do? I will assure the user that I’ll be able
to help them out, and then I will also want to know the network outage symptom. Are you receiving
an error message? Let’s say that I just opened up my laptop and I tried to access one of our
internal websites, I get an error message and it says page can’t be displayed. Okay. Do you know of any other
users are having this issue? No, I’m not sure. It’s
first thing in the morning, and I’m the first one here. Okay. Can you actually give
me the name of the website, I’d like to test
that on my computer. Sure. The URL for the internal website is
intranet.companyx.com. Okay, thanks. I’m going
to test that out. All right. Let’s say that it
loads up fine just for you. Okay. Now I want you try
out external website, so maybe try Google.com. I get the same result
on Google.com, page can’t be displayed. Okay. What OS are you using? Let’s say I’m using Windows 7. I want you to navigate
to command prompt. The way you could do
that is just going to Start menu and search CMD. Let’s say I launch that, I have my black command
prompt window open. Now, can you run the
command ipconfig/all. I do that and I see
a bunch of things. I see IP address, default gateway, DNS,
and I’m a curious user. Can you explain to me what
all those things mean? Yes. IP address is a unique
numerical address given to computing devices to communicate on the Internet to
other computers. Default gateway serves as an
access point that’s used by computers to send information to another computer
or on the Internet. That can be a router. DNS is domain name system, so that translate domain
names into IP addresses. Great. Let’s say I read you
all this info and I tell you my IP address is 192 dot
something dot something. But you know that
our network only uses addresses in the range of 172 dot something dot something.
Does that mean anything? Yeah. Does this
machine use DHCP? It does. But since
you brought that up, can you explain to
me what DHCP is? Yes. Dynamic Host
Configuration Protocol automatically assigns IP
addresses to computing devices, and it can also send
network configurations too. Why would that be important
in this scenario? This will be important
just because if the IP addresses getting
assigned statically, then we have to go
in and change it, but it should be in the
site automatically. Back to our scenario. What are some reasons
I might be getting the wrong IP address from DHCP? DHCP can be configured
incorrectly, or you could be connected
to the wrong network. Let’s start with the
more simple explanation. How can we check what
network I’m connected to? Do you know if
you’re connected to wired or wireless network? I’m on my laptop,
so I’m on wireless. If you’re on
wireless, let’s go to the bottom-right corner and
click on the Wi-Fi symbol, and then go into
network preferences just to see what network
you’re actually connected to. When I do that, you’re right, I’m connecting to some random
network across the street. Once I switch back to
our corporate wireless, it seems to solve the issue. I guess the network
wasn’t down after all. Good job. In this scenario, we saw a great example of
asking clarifying questions. Problem started with the user saying that the
network was down. That can actually
mean many things. It’s important to figure
out what exactly is going wrong before we start
trying to fix things. We also saw a few
examples of having to explain the terms we use
during the interview. If you use a term
like DNS or DHCP, it’s important that
you know what it means and how it
might be relevant. That’s it for now. See you again at the end of
the next course.

You did it, you should be
really proud of yourself because getting through all of this material is a
huge accomplishment. The material we’ve
covered has been pretty technical and
super complicated. Getting through it
all is a real feat. Take a moment to think about just how much
you’ve learned. You now know a lot about how computers communicate
with each other, which is an essential part of how people communicate
with each other. Computer networks are used
by billions of people every day and they form the backbone of the
global economy. You’ve learned about
how signals are carried across cables and how many different
protocols are used in conjunction to make sure this
data is delivered properly. You’ve learned about
all network services like DNS that help
humans use computers. This is all very
important to learn. You’ll be able to apply all of this knowledge into
your IT support career. You can also just use it to help your own home
network run better. Either way, congrats, you’ve
given yourself a leg up. Next time you visit a social media site
or stream a video, or even just chat with your
friends and family online, take a moment to think
about how amazing it is that so many different
network devices and layers and protocols
are involved with every little bit of data
sent across the Internet. You should also take a moment to marvel at the fact that you now understand how all of that
works, congratulations. In the next course,
operating systems in you becoming a power user, my friend and
colleague, Cindy Quach, will be your guide as you navigate the Windows
and Linux OS’s. Get ready to have some fun
and get your hands dirty as Cindy teaches you how to
become a command line wizard.

I think a big misconception that a lot of people have about IT, or tech work in general, is that it’s complicated
or that it’s difficult, or that only some
small subset of people are capable of
handling these tasks. None of that is true. These are very specific skills that you have to know and that’s
absolutely true. Maybe it’s true that most
people don’t have these skills, but that doesn’t mean
that people can’t learn. IT is incredibly stable. You have the opportunity to
make a very good living. You have a ton of directions
that your career can go. So many people I know started off in desktop
support and are now network engineers or site reliability engineers
or software engineers. It’s an industry
that’s not going away. It’s only growing. There’s always going
to be opportunities. I studied philosophy and history and actually also minored
in creative writing. While some of those
skills are absolutely transferred and allow
me to excel at my job. I didn’t learn anything about the technical aspects from
my time in college at all. I’ve never taken an academic
computer science course. I’ve never taken a
course in networking. I’ve never taken a course
in anything related to computers in any
way whatsoever. Education is important,
but there are other ways that you
can learn the skills that you need to have a successful career
in IT, in tech.