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protocol

Mcminnville, TN

#1 Jul 28, 2010
There seems to be a ton of confusion on here surrounding exactly what an IP address and how you get one. Let's cover some basics. For computers to communicate, they use what is today called the Internet Protocol, abbreviated IP. Computers don't understand names like cnn.com , they understand numbers. The Internet today uses what is called the Domain Naming Service (DNS) to translate a domain name ( cnn.com ) to an IP address (157.166.255.19, in the case of www.cnn.com ). DNS is like a huge phone book that maps IP addresses to domain names, because no one can memorize all the IP addresses for every site on the Net.

An IP address is a 32-bit number, composed of 4 separate octets (example, 192.168.1.1). To get a "block" or group of IP addresses, an Internet Service Provider (ISP) must approach the ICANN ( http://en.wikipedia.org/wiki/ICANN ) to purchase a block of unused IP addresses. IP networks can be of different classes. For example, a Class C network can only have 256 individual hosts (computers), as the first 3 octets are already used. A Class A network can have over 16 million hosts (computers)! The most common example of this is a home router, which groups your home computers into the 192.168.1.0/24 Class C subnet.

So, your ISP (Ben Lomand, Charter, etc.) buys up a "block" of IP addresses from ICANN. When your DSL modem connects to the ISP, the ISP will assign you (actually, the outside interface of your modem) an unused IP address from the block they purchased. If the ISP uses dynamic IP addressing, your IP will change throughout the day as the "lease" expires. So you might be from "Piney" now and from "Manchester" later depending on how the particular block you are in is registered with ICANN.

Changing a computer won't change your IP address if you are behind the same DSL modem. Only two things will change your IP address: physically going to another PC behind a different DSL modem, or a new, dynamic, IP address being assigned to your DSL modem by your ISP when the lease expires.
protocol

Mcminnville, TN

#2 Jul 28, 2010
Now let's talk a little about what happens when two computers need to communicate. Data travels down what is called a "protocol stack". There are two main models used today to describe these "stacks": the OSI model ( http://en.wikipedia.org/wiki/OSI_model ) and the TCP/IP model. The OSI model has 7 layers which data travel down, all the way from the application (Word, Excel, Internet Explorer, etc.) down to the physical copper wire where it leaves your house as an electrical signal.

In the TCP/IP model, the first 3 layers of the OSI model are combined into a single layer, but the effect is the same. So, let's way you want to visit www.cnn.com . You first open your browser (which operates at Layer 7, the application layer) and type the URL into the address bar and hit enter. Your computer sends an HTTP GET request to the server hosting www.cnn.com by looking up cnn.com 's IP address via the DNS service we discussed earlier. The Transport Layer (Layer 4) sets up the connect between your machine and cnn.com using TCP SYN packets. The Network Layer (Layer 3) then uses the IPs addresses to route the data from your computer to the server at www.cnn.com . So, the TCP portion handles the connection parameters, and the IP portion handles the actual addressing. Think of an IP address as a physical address used by the USPS. If I want to get a package to you, I need your physical address. The Internet is the same - if I want to get a data packet to you, I need a unique address that I can route the data to.

Finally, the data goes down to Layer 1, the Physical Layer, which is the actual copper wire or fiber leaving your home. Data gets passed as a series of electrical impulses which computers translate as 0's or 1's that then get assembled back into meaningful data as the data travels back up the OSI model when it reaches its destination. And of course all this happens at the speed of light (literally), as light is just a form of electromagnetic radiation which is visible to the human eye.
protocol

Mcminnville, TN

#3 Jul 28, 2010
So, how do you determine your particular IP address? You can visit sites like www.whatismyip.com to find out your current IP address. Again, unless your ISP is assigning static IP addresses (meaning they stay the same), your IP address may vary over the course of the day as the "lease" on the current address expires and the ISP assigns you a new one.

If you are on a computer connected directly to a DSL or cable modem that doesn't offer Network Address Translation (NAT), your Network Interface Card (NIC) or "network card" is assigned the IP address directly. If you are behind a home router or a modem that offers NAT, your NIC may have an IP address like 192.168.1.100. This is a reserved Class C address space and is not routable over the Internet. In this case, your ISP will assign the "real" or routable IP address to the outside interface on your DSL modem or router. This is a more secure connection type, as it keeps several exposed TCP/IP ports in the Windows operating system from being exposed directly to the public facing Internet.

If you are using Windows XP, click Start then Run... and then type "cmd" without the quotes into the box. A command prompt will appear. Type "ipconfig /all" without the quotes and hit Enter to see the IP address assigned to your NIC. If you want to find out the IP address of a server you visit, you can type "ping www.cnn.com " without the quotes and hit enter (insert any server name you wish). This will send an ICMP ECHO request packet to the server you specified, and you can see the Domain Name get translated into an IP address. Note, not all servers will respond to a "ping" request, as you can use a Loki attack to hide malicious data inside an ICMP packet.
protocol

Mcminnville, TN

#4 Jul 28, 2010
And, perhaps finally, can you use a person's IP address to identify him or her? Maybe, and maybe not. First, most ISPs have privacy policies in place that prevent unauthorized individuals from getting the name and address of a customer based on his or her IP address. Most government agencies are required to produce a subpoena requiring the ISP to disclose the name and address of a user. Finally, the IP address can only be traced to a given piece of hardware (router, modem, or NIC). If someone uses your PC, for example, the traffic can be traced back to YOUR computer, but it doesn't mean that you initiated the traffic in question.
Uncle Larry

Mcminnville, TN

#5 Jul 28, 2010
Great tutorial, want to let the folks know about proxy hosting? LOL.
protocol

Mcminnville, TN

#6 Jul 28, 2010
Uncle Larry wrote:
Great tutorial, want to let the folks know about proxy hosting? LOL.
That would be the next logical step, yes. You can configure your Internet browser (Internet Explorer, Firefox, Chrome) to connect to the Internet via a proxy server, which helps to anonymize you as you browse the web. Other proxies are Web-based, meaning you put the URL of the proxy server into your browser's address bar, then from the proxy site you enter the DNS name of the server you wish to really visit. One popular solution popular today is Tor, which you can read about here http://en.wikipedia.org/wiki/Tor_anonymity_ne...

“Yoga Alliance : NamaSpirit”

Since: Nov 08

Kindred Spirits-4-Love

#7 Jul 28, 2010
I presume you might work for Ben Lomand? In any case thanks for sharing the information with us here.
protocol

Mcminnville, TN

#8 Jul 28, 2010
deZengo wrote:
I presume you might work for Ben Lomand? In any case thanks for sharing the information with us here.
No, but I work in network administration and information security.
NBC

Sparta, TN

#9 Jul 28, 2010
Thank you for this useful information. Maybe it will shut that idiot "Get a life" person up. The Spencer ip address one computer theory was really getting annoying .
protocol

Sparta, TN

#10 Jul 28, 2010
No problem. It's nice to be able to share knowledge and clear up misunderstandings.
protocol

Sparta, TN

#11 Jul 28, 2010
One final thought for the night: most networks today are behind a home or work router or firewall. In this case, you might have hundreds of PCs with the same outward, public facing IP address. This happens through Network Address Translation (NAT) and Port Address Translation (PAT). Basically, your computer's network card is assigned an internal, non-routable IP address by the router/firewall. The firewall or router's outward, public interface will have the routable, ISP-assigned IP address. This is what keeps us from currently running out of IP version 4 (IPv4) Internet addresses. For example, a Class C subnet can have 256 (254 technically) devices on a subnet sharing the same public IP address. So anyone posting from a machine at work will have the "same" IP address as far as Topix (or any other site for that matter) are concerned.

In the coming years, IPv6 will become the standard, and billions of devices will have routable IP addresses. Everything from your washer and dryer (set them to start just before you leave the office, maybe) to your dishwasher and toaster will potentially have NICs and "touch" the public Internet.
May I Ask

Sparta, TN

#12 Jul 28, 2010
protocol wrote:
One final thought for the night: most networks today are behind a home or work router or firewall. In this case, you might have hundreds of PCs with the same outward, public facing IP address. This happens through Network Address Translation (NAT) and Port Address Translation (PAT). Basically, your computer's network card is assigned an internal, non-routable IP address by the router/firewall. The firewall or router's outward, public interface will have the routable, ISP-assigned IP address. This is what keeps us from currently running out of IP version 4 (IPv4) Internet addresses. For example, a Class C subnet can have 256 (254 technically) devices on a subnet sharing the same public IP address. So anyone posting from a machine at work will have the "same" IP address as far as Topix (or any other site for that matter) are concerned.
In the coming years, IPv6 will become the standard, and billions of devices will have routable IP addresses. Everything from your washer and dryer (set them to start just before you leave the office, maybe) to your dishwasher and toaster will potentially have NICs and "touch" the public Internet.
Where are you from? Nobody in Spencer has this much knowledge!
Uncle Larry

Mcminnville, TN

#13 Jul 28, 2010
IPv6 has a name, its called Skynet.
protocol

Sparta, TN

#14 Jul 29, 2010
May I Ask wrote:
<quoted text>
Where are you from? Nobody in Spencer has this much knowledge!
I'm a Van Buren native. I've lived with and used personal computers all my life. I've managed small networks for a decade. All of this information seems complex (and in many ways it is), but it is freely available. The Internet is based on standards. Common standards are what allows any Ethernet-based network to "talk" to any other Ethernet-based network even though they have different hardware and software. This what lets your Dell desktop with a Broadcom NIC talk to a Web server a thousand miles away hosting a site on Apache Web Server running on a Linux operating system with a 3COM NIC. Everything about the TCP/IP protocol suite is freely available in the form of what is called a Release For Comment(RFC). You can also discover this knowledge by simply reading books from Amazon and by experimenting on your own home network. Knowing several Computer Science majors helps as well.
protocol

Sparta, TN

#15 Jul 29, 2010
Uncle Larry wrote:
IPv6 has a name, its called Skynet.
Having seen the Terminator series, we know the solution: what ever you do, do NOT try to unplug teh Skynetz!!
protocol

Sparta, TN

#16 Jul 29, 2010
Let's dig a little deeper into what we mean by a 32-bit address and "running out" of IPv4 IP addresses. We said earlier that an IP address is a 32-bit address made up of 4 octets. For example, most home routers use the 192.168.1.0/24 Class C subnet when assigning IP addresses to the computers behind them. That 192.168.1.0 address is understood by humans, but not by the computer. Again, the computer uses what is called "binary", meaning a 1 or a 0. So, to a computer, an IP address looks like this: 00000000.00000000.00000000.000 00000 which is 32 "bits" (8 in each octet) with a "bit" being able to be a 1 or a 0. As you work across the field of bits in each octet from right to left replacing 0's with 1's, you increase the corresponding number that we humans understand and associate with an IP address. If we make the last (furthest left) 0 in the octet a 1, we now have a human number of 256. Since each bit can have 2 values (1 or a 0), everything in binary is based on squares or the second power. Again, working left to right filling in the 0's with 1's, we could have values of: 256, 128, 64, 32, 16, 8, 4, 2, and 1. Thus if the first number in our IP address is 11101011 in binary, the first number of our IP address in human understanding is 237. That is: 128+64+32+8+4+1.

Since the each octet is only 8 bits, the most you can have is 256.256.256.256, and doing the math of 256x256x256x256 gives us a total of 4,294,967,296 IPv4 addresses. Four billion is not a lot if you think about how many devices capable of using TCP/IP exist! Think about how many PCs companies like Dell have on their network alone, for example. This is why we use NAT and PAT as discussed earlier to put PCs behind a router or firewall on a private subnet with non-routable IP addresses like 192.168.1.1 (which in binary is 11000000.10101000.00000001.000 00001).
protocol

Sparta, TN

#17 Jul 29, 2010
Here is a great introduction on binary and will show you the breakdown of the process I described above
http://www.networkclue.com/hardware/computer/...
catdaddy

Maryville, TN

#18 Jan 28, 2011
protocol wrote:
Let's dig a little deeper into what we mean by a 32-bit address and "running out" of IPv4 IP addresses. We said earlier that an IP address is a 32-bit address made up of 4 octets. For example, most home routers use the 192.168.1.0/24 Class C subnet when assigning IP addresses to the computers behind them. That 192.168.1.0 address is understood by humans, but not by the computer. Again, the computer uses what is called "binary", meaning a 1 or a 0. So, to a computer, an IP address looks like this: 00000000.00000000.00000000.000 00000 which is 32 "bits" (8 in each octet) with a "bit" being able to be a 1 or a 0. As you work across the field of bits in each octet from right to left replacing 0's with 1's, you increase the corresponding number that we humans understand and associate with an IP address. If we make the last (furthest left) 0 in the octet a 1, we now have a human number of 256. Since each bit can have 2 values (1 or a 0), everything in binary is based on squares or the second power. Again, working left to right filling in the 0's with 1's, we could have values of: 256, 128, 64, 32, 16, 8, 4, 2, and 1. Thus if the first number in our IP address is 11101011 in binary, the first number of our IP address in human understanding is 237. That is: 128+64+32+8+4+1.
Since the each octet is only 8 bits, the most you can have is 256.256.256.256, and doing the math of 256x256x256x256 gives us a total of 4,294,967,296 IPv4 addresses. Four billion is not a lot if you think about how many devices capable of using TCP/IP exist! Think about how many PCs companies like Dell have on their network alone, for example. This is why we use NAT and PAT as discussed earlier to put PCs behind a router or firewall on a private subnet with non-routable IP addresses like 192.168.1.1 (which in binary is 11000000.10101000.00000001.000 00001).
Yeah I totally knew that.
true or false

Monteagle, TN

#19 Jun 10, 2011
protocol wrote:
No problem. It's nice to be able to share knowledge and clear up misunderstandings.
is it true that there is a way to have your IP number change each time you use the computer?
Thank you

Cookeville, TN

#21 Jun 20, 2011
I have a friend who travels all over the country. No matter where he is, as long as he has an internet connection, his City always shows the same. He said he purchased it like that. How can he get on someone else's internet connection 1200 miles away and show the same city?( This is a small city in Tennessee). Most of the time he says he's on the road or in a rest area. Sorry, but I don't understand how that works. How can he be on the internet from a laptop if he doesn't have an internet connection from his car?

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