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IP Address Explained and How to Quickly Figure out Yours

If you’ve ever tried troubleshooting your home network or setting up a new router, you must have heard of IP address or IP for short.

This post will explain more — in layman’s terms — about this type of address, IPv4 vs. IPv6, and help you find out yours at any given time.

But first, hit the GO button in the speed test below. You’ll immediately see an IP address at the lower-left corner of the test window, under the name of your current ISP. That’s your WAN IP address. Keep it in mind.

• This test will use up your data and Ookla may collect certain information from your Internet connection.

What is an IP address

IP stands for Internet protocol. IP addresses are how devices identify themselves and talk to one another over the Internet or within a local network.

When you surf a website or browse a network computer, you access a particular IP address. A meaningful domain or computer name — such as dongknows.com or Server — is just a helpful way to mask that address so that we humans can remember.

By the way, binding an IP address with a meaningful name is the job of a DNS server.

A device can’t get connected if it doesn’t have an IP address, which is uniquely assigned to each network member by a DHCP server (your router). In other words, you can’t have two devices sharing one IP address in the same network and expect them to work correctly, if at all.

(To avoid an IP conflict, refrain from manually assigning a static address to a device.)

Within a local network, generally, the IP address of each member device remains the same for the duration it is on and connected. When you restart the device, its IP address might change unless you choose to reserve the same address for it by binding the IP with the device’s MAC Address.

Asus RT AX68U 5
In a home network, the route manages all the local IP addresses.

IPv4 vs. IPv6

There are two versions of Internet protocol, IPv4 and IPv6. The former is the most popular and generally the default connotation of an IP address. (You’ll need to call the latter an IPv6 address explicitly). The truth is, the popularity of IPv4 is the reason why we need IPv6.

Though IPv6 is newer and has been available for a few years. Generally, though, for the most part, we’re still dealing mostly with IPv4 now and long in the future.

Internet protocol version four (IPv4)

IPv4 uses a 32-bit pool of addresses. As a result, a typical IPv4 address consists of four groups of three-digit numbers with a dot (.) in between, like this one: 192.168.010.002

You can omit the leading zeros in each group in an IP address, but each group must retain at least one digit. That said, the address above usually appears as 192.168.10.2

When you change a number, we have a new address, so mathematically, IPv4 can produce 4,294,967,296 — four billion and then some — addresses.

While that seems like a lot, there are about 10 billion people globally, and one of us can have more than one device. It’s quite inevitable that at some point, IPv4 will run out of addressing space.

Extra: WAN vs. LAN vs. NAT

To conserve the addresses, IPv4 is available at two levels: Wide Area Network (WAN) and Local Area Network (LAN).

At the WAN — or Internet — level, the address is always unique at any given time. Generally, each website has a WAN IP address. At your home, your router (or gateway) has your WAN IP — the one you found out on top of this post.

The router then creates a sub-level LAN network with a different set of local (or private) IP addresses for other devices, like your computers or tablets, to use.

Effectively, this allows multiple devices to access the Internet via a single WAN (or public) IP address, instead of each having a WAN IP of its own. The router does that via a function called network address translation, or NAT.

See also  Double NAT vs. Single NAT: How to Best Handle an (ISP-Provided) Gateway

That said, in your home, other than the router, the rest of the devices uses LAN IP addresses that are unique only within the home network.

So you might find a computer at home that has the same LAN address as another at your friend’s. This duplication is possible because the two are “shielded” behind each home’s router’s unique WAN IP address.

This shielding also has another bonus. Devices connected to a router are behind a layer of protection from the outside world. Depending on the router in use and how you configure it, you can keep the entire network safe from identity thieves and other online threats.

By the way, the use of NAT is so effective that I believe IPv4’s address pool will suffice for a very long time in the future. That’s not to mention many existing IPv4-only devices will last ages more and need to be supported.

So IPv4 is not going away anytime soon, if at all. In any case, you can always choose to use it within your local network. But, still, we need something more robust, and that’s the slot IPv6 fills.

You can configure your IPv4 address pool using your router's interface.
You can configure your IPv4 address pool using your router’s interface.

Internet protocol version six (IPv6)

IPv6 uses a much larger 128-bit pool of addresses. A typical IPv6 address includes 8 groups of four characters (numbers or letters), divided by colons (:) and looks like this: 2001:0cd8:85e6:0000:0000:8e2c:0450:8733 or 2001:cd8:85e6:0:0:8e2c:450:8733 (leading zeros can be omitted).

While still finite, the total number of IPv6 addresses is exponentially higher than IPv4’s. Specially, you can get 340,282,366,920,938,463,463,374,607,431,768,211,456 — that’s 340 trillion trillion trillion and then a couple of hundreds of trillion trillion more — addresses out of IPv6.

At this level, it’s safe to say we’ll never run out of addressing space. And that’s great but can also bring about some privacy concerns. The reason is IPv6 means there’s no need to conserve the addresses anymore.

Extra: Privacy concerns

Among other things, the IPv6 address assigned to each device at any given time can now be unique globally — universally, in fact. In other words, IPv6 addresses are generally always the WAN addresses.

Consequently, when your computer connects to the Internet using IPv6, it’s exposed to the outside world. Thus, folks on the other end — like the website you visit — can trace back directly to it, instead of the router, like the case of IPv4.

As a result, among other things, they can potentially tie certain online activities to a specific user. And that implies a lot of things.

Currently, all home networks still use IPv4, with some also using IPv6 alongside. Most home routers support IPv6, but only a few service providers support this new protocol.

You can choose to disable IPv6 at the router level or an individual device most of the time. And if you should do that if you don’t want to deal with the new protocol or have privacy concerns.

How to find out your local IP addresses

Again, a local IP address belongs to a device within your home network, and we’re talking mostly about IPv4 here. By the way, you generally can change the scheme of your local IPs via your router’s interface.

The ipconfig /all command reveals a lot of information about your network.
The ipconfig /all command reveals a lot of information about your network.

How to find out the IP address of a Windows computer

  1. Click on the Start button then type in cmd then press Enter. The Command Prompt will appear.
  2. Type in ipconfig or ipconfig /all then press Enter. (The latter command reveals more information.)

Now you will see the local IP address (both IPv4 and IPv6) of your computer and the Default Gateway address, or your router’s. By the way, if you use the ipconfig /all command, you’ll also see the MAC address (shown as Physical Address).

Pro tip: Opening the Gateway IP address in a browser (like Chrome) will take you to your router’s web interface (most routers have one). Among other things, you can use the interface to change the IP settings of your network and find out the IP address of all connected clients in a network — more blow.

See also  MAC Address Explained and How You Can Change Yours

How to find out the IP address of a Mac computer

For Wi-Fi users:

Click on the Wi-Fi icon (top right) while holding down the Option key. You will see a menu with loads of information about the connection, including the IP addresses of your computer and the router.

You can quickly view lots of information about your Wi-Fi connection, including your IP address, with an Option + Click on a Mac.
You can quickly view lots of information about your Wi-Fi connection, including your IP address, with an Option + Click on a Mac.

If your Mac connects via a network cable, then do this:

  1. Click on the Apple icon (top left) then System Preferences.
  2. Find the Network icon and click on it.
  3. Click on the current connection. Here you’ll find the information you need.

How to find out the IP address of any device in a local network

This part applies to a network with multiple connected devices, and you want to find out the IP address of any particular one among them.

This trick is helpful when you need to configure that device — be it a printer or an access point or an IP camera — using the computer you are using. It’s also useful when you want to know the IP of another computer in the network that you’re not using.

An example of a connected client list within a router's web interface. Note the MAC and IP addresses.
An example of a connected client list within a router’s web interface. Note the MAC and IP addresses.

To figure out the IP address of another device in the network, you need to have access to the network’s DHCP server — in most cases, that’s the router. Here are the steps:

  1. Log in the router’s web interface using its IP address — see the Pro-tip above.
  2. Navigate to the LAN section of the interface and then the DHCP server section. Some routers have a network map that shows the connected clients and their IP addresses.
  3. Here, you’ll see the list of connected clients. Most of the time, they have their names listed. If not, you can always find out which one is which by their MAC address.

Once you have determined the IP address of a device, you can use it to access it. If the device has a web interface — most printers and Wi-Fi access points do — you can open this interface via its IP address.

Extra: When and how to reserve an IP address for a device

Reserving an IP address (or a DHCP address) binds a device’s MAC address with an IP address. From then on, the router will keep that particular IP for that specific MAC address. So, every time the device connects to the network, it will get that same IP address.

This setting is helpful in situations where you don’t want the device’s IP to change. Examples are when you use a network printer, a network security camera, or a server of any kind. When the IP changes, the application you’ve set up with the particular device might not work anymore. It’s always so in the case of port-forwarding.

While you don’t need the reserve the IP for all connected clients, it doesn’t hurt if you do so, either.

IP Reservation
On Linksys router, you can easy to reserve an IP address on the Network map.

The steps to make an IP reservation vary from one web interface to another, but you can almost always do that at the place where you can view the list of connected clients or the network map.

Most home routers — those from Asus, TP-Link, D-Link, Netgear, Synology — allow you to do that via a click. With others, you might have to enter the MAC address and the IP address manually.

More on WAN IP address

The WAN IP address is the unique address that represents your entire home network to the Internet. For this reason, it’s known as your public IP address. You can instantly look up your  WAN IP address at the top of this post. Or you can Google “What’s my IP.”

Generally, your service provider assigns the WAN IP address to your home router (via the modem), and you can’t change it.

Note that this public address tends to change once in a while in most cases unless you pay for a static IP, which is expensive.

That said, you can’t just write it down and expect to be able to dial home when you want. To keep tabs on your WAN IP — when you’re away from home — you need to use a Dynamic DNS service. And that deserves a different post entirely.

Dong’s note: I originally published this post on Feb 15, 2018, and have updated it since to add relevant information.

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6 thoughts on “IP Address Explained and How to Quickly Figure out Yours”

  1. Thanks for having a place where I can find as much info as I need for any situation. I would start with one article and I would find myself exploring even more info.

    If I’m reading the things correctly (pretty new at all the info about setting up a mesh system down the road (from a pitiful extender), does the Gateway’s IP address represent the Gateway’s router, which is their WAN IP? Is it this address that I need to make sure the new router does not have the same if I’m going to set up the new router in Bridge Mode? Do I change this IP before I enable Bridge Mode?

    Reply
    • Generally, Laura, a router’s (or a gateway)’s default IP address, the one you can use to access its web user interface, is called the “Default Gateway” address. (NOT “Gateway’s IP address” — note the apostrophe). The word “Gateway” in this case has NOTHING to do with what a gateway is.

      And no, that’s NOT its WAN IP, which changes. But yes, from outside (the WAN side), you can use its WAN IP to access its interface, too, if you turned on the remote management — more here.

      Again, when talking about a router, keep this in mind:

      1. Gateway IP address (or default IP address) is referred to the IP address of the router itself, which is unique locally. It represents the fact the router is the HOST of a network.
      2. WAN IP address: It’s the IP address the router gets from the ISP (or any Internet source including another router). It represents the fact the router is a MEMBER of a larger network outside of the one it hosts — the world wide web.

      That said, I’d recommend you read this post (and others) again and get the definitions down. You’re getting close. Using names arbitrarily will make it impossible for anyone to know what you’re talking about.

      Reply
  2. Hi Dong

    Thanks for the explanation. Its very usefull. I have a question regarding the IP address for use in home networks. Did you recommend to use the standard 192.168.1.xx or it is recommend for security to start with different range that the ones that comes in a router. Is there any issue, Let me know your comments and suggest.

    thank

    Reply
    • Sure, Hector. Technically, it doesn’t matter, but personally I’d change 1 into something else, like your lucky number — mine is 13 :). That way, you can avoid conflicts in some cases, and always know for sure if a device get the IP from your router’s pool.

      Reply
  3. I thought it was interesting when you explained that an IP address is how a device can identify itself over the internet. If I remember correctly, someone recently told me that people can buy and sell IP addresses if they want to get a specific one. It would be interesting to learn more about how this process of buying and selling works.

    Reply
    • Among other things, it works by not spending time and spamming the audience of a website with the business’s link, Henry.

      Reply

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