how to know what ip addresses are being used

Every device connected to a network—computer, tablet, camera, whatever—needs a unique identifier and so that other devices know how to reach it. In the world of TCP/IP networking, that identifier is the Internet Protocol (IP) accost.

If yous've worked with computers for whatever amount of time, you've likely been exposed to IP addresses—those numerical sequences that expect something like 192.168.0.15. Most of the time, we don't have to deal with them directly, since our devices and networks take intendance of that stuff behind the scenes. When nosotros practice have to deal with them, we often simply follow instructions about what numbers to put where. Simply, if you've ever wanted to dive a picayune deeper into what those numbers mean, this article is for you.

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Why should yous intendance? Well, understanding how IP addresses piece of work is vital if you lot ever want to troubleshoot why your network isn't working right, or why a particular device isn't connecting the way you'd expect it to. And, if you always demand to fix up something a niggling more than advanced—like hosting a game server or media server to which friends from the internet can connect—you'll demand to know something nearly IP addressing. Plus, it's kind of fascinating.

Note: We're going to be covering the basics of IP addressing in this commodity, the kind of stuff that people who use IP addresses, simply never actually idea much about them, might want to know. We're non going to be covering some of the more avant-garde, or professional, level stuff, like IP classes, classless routing, and custom subnetting…but we will indicate to some sources for further reading as we go along.

What Is an IP Address?

An IP address uniquely identifies a device on a network. You've seen these addresses before; they await something like 192.168.ane.34.

An IP address is e'er a set of four numbers similar that. Each number can range from 0 to 255. So, the full IP addressing range goes from 0.0.0.0 to 255.255.255.255.

The reason each number tin can only reach upwards to 255 is that each of the numbers is actually an eight digit binary number (sometimes chosen an octet). In an octet, the number goose egg would be 00000000, while the number 255 would be 11111111, the maximum number the octet tin reach. That IP accost nosotros mentioned before (192.168.one.34) in binary would await like this: 11000000.10101000.00000001.00100010.

Computers piece of work with the binary format, merely we humans find information technology much easier to work with the decimal format. Still, knowing that the addresses are actually binary numbers will help us sympathize why some things surrounding IP addresses work the manner they do.

Don't worry, though! We're non going to be throwing a lot of binary or math at you in this article, so merely deport with us a bit longer.

The Two Parts of An IP Address

A device'due south IP accost actually consists of two divide parts:

• Network ID: The network ID is a part of the IP accost starting from the left that identifies the specific network on which the device is located. On a typical home network, where a device has the IP address 192.168.1.34, the 192.168.1 part of the address will be the network ID. It's custom to fill in the missing last function with a zero, so we might say that the network ID of the device is 192.168.1.0.
• Host ID: The host ID is the office of the IP address non taken up past the network ID. Information technology identifies a specific device (in the TCP/IP world, nosotros call devices "hosts") on that network. Continuing our example of the IP address 192.168.ane.34, the host ID would be 34—the host's unique ID on the 192.168.ane.0 network.

On your home network, so, y'all might see several devices with IP address like 192.168.one.one, 192.168.1.2, 192.168.one 30, and 192.168.one.34. All of these are unique devices (with host IDs 1, 2, thirty, and 34 in this case) on the same network (with the network ID 192.168.ane.0).

To picture all this a little ameliorate, permit'due south turn to an analogy. Information technology'due south pretty similar to how street addresses work inside a city. Take an accost like 2013 Paradise Street. The street proper noun is like the network ID, and the house number is like the host ID. Within a city, no ii streets volition be named the same, just like no two network IDs on the same network will exist named the same. On a particular street, every house number is unique, just like all host iDs within a particular network ID are unique.

The Subnet Mask

So, how does your device determine which part of the IP address is the network ID and which part the host ID? For that, they use a second number that yous'll always see in association with an IP address. That number is called the subnet mask.

On most simple networks (similar the ones in homes or small businesses), you'll come across subnet masks like 255.255.255.0, where all four numbers are either 255 or 0. The position of the changes from 255 to 0 indicate the division between the network and host ID. The 255s "mask out" the network ID from the equation.

Note: The basic subnet masks nosotros're describing hither are known as default subnet masks. Things go more complicated than this on bigger networks. People often use custom subnet masks (where the position of the break between zeros and ones shifts within an octet) to create multiple subnets on the same network. That's a little beyond the scope of this article, but if you're interested, Cisco has a pretty skilful guide on subnetting.

The Default Gateway Address

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In improver to the IP address itself and the associated subnet mask, y'all'll besides see a default gateway address listed along with IP addressing information. Depending on the platform you lot're using, this accost might be called something dissimilar. Information technology's sometimes chosen the "router," "router address," default route," or just "gateway." These are all the aforementioned matter. It's the default IP address to which a device sends network data when that information is intended to become to a different network (1 with a different network ID) than the one the device is on.

The simplest example of this is found in a typical domicile network.

If you lot have a home network with multiple devices, you probable have a router that'due south continued to the internet through a modem. That router might exist a dissever device, or it might be office of a modem/router combo unit supplied past your cyberspace provider. The router sits between the computers and devices on your network and the more public-facing devices on the cyberspace, passing (or routing) traffic back and forth.

Say you lot fire upwards your browser and caput to www.howtogeek.com. Your estimator sends a request to our site's IP address. Since our servers are on the internet rather than on your dwelling network, that traffic is sent from your  PC to your router (the gateway), and your router forwards the request on to our server. The server sends the right information back to your router, which and so routes the information back to the device that requested it, and you lot run into our site popular upward in your browser.

Typically, routers are configured by default to have their private IP address (their address on the local network) as the first host ID. Then, for example, on a domicile network that uses 192.168.i.0 for a network ID, the router is ordinarily going to exist 192.168.i.i. Of class, like most things, you can configure that to be something different if yous want.

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DNS Servers

There'south one final piece of information you'll see assigned alongside a device's IP accost, subnet mask, and default gateway address: the addresses of one or two default Domain Proper noun Organisation (DNS) servers. We humans work much better with names than numerical addresses. Typing world wide web.howtogeek.com into your browser's address bar is much easier than remembering and typing our site's IP accost.

DNS works kind of like a phone book, looking upwardly human being-readable things like website names, and converting those to IP addresses. DNS does this by storing all that information on a system of linked DNS servers beyond the internet. Your devices need to know the addresses of DNS servers to which to ship their queries.

RELATED: What Is DNS, and Should I Use Another DNS Server?

On a typical small or home network, the DNS server IP addresses are ofttimes the same equally the default gateway address. Devices ship their DNS queries to your router, which and so forwards the requests on to whatsoever DNS servers the router is configured to use. By default, these are usually any DNS servers your ISP provides, simply you can alter those to utilize dissimilar DNS servers if you lot desire. Sometimes, y'all might take better success using DNS servers provided by 3rd parties, like Google or OpenDNS.

What's the Difference Between IPv4 and IPv6?

You besides may accept noticed while browsing through settings a different type of IP address, chosen an IPv6 address. The types of IP addresses nosotros've talked about so far are addresses used by IP version four (IPv4)—a protocol developed in the late 70s. They use the 32 binary bits nosotros talked about (in four octets) to provide a total of iv.29 billion possible unique addresses. While that sounds like a lot, all the publicly bachelor addresses were long agone assigned to businesses. Many of them are unused, but they are assigned and unavailable for general use.

In the mid-90s, worried about the potential shortage of IP addresses, the net Engineering Task Force (IETF) designed IPv6. IPv6 uses a 128-fleck address instead of the 32-scrap address of IPv4, and so the total number of unique addresses is measured in the undecillions—a number big enough that it's unlikely to ever run out.

Dissimilar the dotted decimal notation used in IPv4, IPv6 addresses are expressed equally viii number groups, divided by colons. Each group has 4 hexadecimal digits that represents 16 binary digits (and so, it'due south referred to every bit a hextet). A typical IPv6 address might look something like this:

2601:7c1:100:ef69:b5ed:ed57:dbc0:2c1e

The thing is, the shortage of IPv4 addresses that acquired all the business ended up being mitigated to a large extent by the increased utilise of private IP addresses backside routers. More and more people created their own private networks, using those private IP addresses that aren't exposed publicly.

So, even though IPv6 is even so a major player and that transition will nonetheless happen, it never happened every bit fully as predicted—at to the lowest degree not notwithstanding. If you're interested in learning more, bank check out this history and timeline of IPv6.

How Does a Device Get Its IP Address?

Now that you know the basics of how IP addresses work, let's talk about how devices get their IP addresses in the first place. There are actually two types of IP assignments: dynamic and static.

RELATED: How to Notice Any Device's IP Address, MAC Address, and Other Network Connexion Details

A dynamic IP address is assigned automatically when a device connects to a network. The vast bulk of networks today (including your home network) use something called Dynamic Host Configuration Protocol (DHCP) to make this happen. DHCP is built into your router. When a device connects to the network, it sends out a circulate message requesting an IP address. DHCP intercepts this bulletin, and then assigns an IP address to that device from a pool of bachelor IP addresses.

At that place are sure private IP address ranges  routers will use for this purpose. Which is used depends on who made your router, or how you have gear up things upward yourself. Those private IP ranges include:

• 10.0.0.0 – ten.255.255.255: If yous're a Comcast/Xfinity client, the router provided past your ISP assigns addresses in this range. Some other ISPs as well use these addresses on their routers, as does Apple on their Drome routers.
• 192.168.0.0 – 192.168.255.255: Most commercial routers are set up to assign IP addresses in this range. For example, most Linksys routers utilise the 192.168.1.0 network, while D-Link and Netgear both use the 198.168.0.0 range
• 172.xvi.0.0 – 172.16.255.255: This range is rarely used by whatever commercial vendors by default.
• 169.254.0.0 – 169.254.255.255: This is a special range used by a protocol named Automatic Private IP Addressing. If your computer (or other device) is set to call back its IP accost automatically, simply cannot find a DHCP server, it assigns itself an accost in this range. If you run across i of these addresses, it tells you that your device could not reach the DHCP server when information technology came time to get an IP address, and you may take a networking issue or trouble with your router.

The thing about dynamic addresses is that they can sometimes change. DHCP servers lease IP addresses to devices, and when those leases are up, the devices must renew the lease. Sometimes, devices will get a different IP address from the pool of addresses the server can assign.

Well-nigh of the time, this is not a large deal, and everything will "but piece of work". Occasionally, still, you might want to give a device an IP address that does not change. For example, maybe y'all have a device that you lot demand to access manually, and you lot discover it easier to remember an IP address than a proper noun. Or maybe y'all have certain apps that tin can but connect to network devices using their IP address.

In those cases, y'all can assign a static IP address to those devices. At that place are a couple of ways to do this. You lot tin can manually configure the device with a static IP accost yourself, although this can sometimes be janky. The other, more elegant solution is to configure your router to assign static IP addresses to certain devices during what would normally exist dynamic assignment past the DHCP server. That fashion, the IP accost never changes, just you don't interrupt the DHCP process that keeps everything working smoothly.

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Source: https://www.howtogeek.com/341307/how-do-ip-addresses-work/

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