IPv4 Resource Center

An IP address is an Internet Protocol address. It is a number used to identify and locate a device on a network that uses the Internet Protocol (like the Internet). There are two versions: IPv4 and IPv6. IPv4 is everywhere, while only about 30% of devices can use IPv6. A device with only IPv4 can’t speak to a device with only IPv6, but most devices with IPv6 either speak both protocols or use a translator.

The IP address is not the same as a domain name. A domain name like hilcostreambank.com or IPv4.global might have servers named www, such as www.IPv4.Global. When you visit a web server, your computer looks up the name www.IPv4.Global to get an IP address like 104.24.109.136 (IPv4) or 2606:4700:3031::6818:6d88 (IPv6). Your computer then sends a packet of information to that address, using its own return address. The server replies with a packet to your address.

The number of addresses in IP is determined by the format. Computers use binary digits (0 and 1 are the only possible numbers) (binary digits are “bits”), so a 32-digit number has a possible range of 0 to 2 to the 32^nd power, roughly equal to 4.3 billion possible addresses. That’s IPv4, and 4.3 billion seemed like a lot of addresses in the 1970s, but on today’s Internet seems limited.

That’s why IPv6 has 2 to the 128^th power of addresses, or about 340 trillion trillion trillion (or 340 undecillion). And that in turn is why hexadecimal is used in IPv6 addresses; trying to type a complete IPv6 address in regular decimal notation would take many more digits.

Because there are only about 4.3 billion possible IPv4 addresses, a few measures have been created to use those addresses more efficiently. One very common mechanism is called NAT, for Network Address Translation.

NAT is used to share one IPv4 address among multiple computers. The NAT device (like a home wifi router or a company firewall) sits between a private network and the Internet. The computers (or phones, printers, or other devices) themselves will have private IP addresses, from one of the reserved block of private IPv4 addresses: 192.168.0.0/16, 172.16.0.0/12, or 10.0.0.0/8. The NAT device has a public IPv4 address (pretty much any other set of numbers between 0.0.0.0 and 223.255.255.255; numbers above 224.0.0.0 are reserved for other special uses).

Private IPv4 addresses are reused by all private networks. It doesn’t matter that they overlap, because the NAT devices make them appear to the rest of the Internet as if they’re using public IPv4 space. Since that IPv4 space is limited, there is a market for IPv4 addresses. Companies can buy IPv4 or sell IPv4 on https://ipv4.global/auctions .

65,536. The /16 notation refers to CIDR (Classless Inter-Domain Routing, but everyone just says “cider”). The number after the slash tells you how many bits are used to define the network. Since there are 32 bits in an IPv4 address, a /16 uses 16 bits to define the network; the remaining 16 bits are used to address hosts. So there are 2 to the (32-16) addresses in a /16, for 65,536.

In a /24, there are 2^(32-24) or 2^8 or 256 possible addresses.

A handy Excel spreadsheet formula is =power(2,32-CIDR) where CIDR is the number after the slash.

It’s also possible to have an IPv6 /16, like 2001:db8::/16. Since there are 128 bits in IPv6, a /16 has 2 to the (128-16) or 2^112 or. . . well, really a lot of addresses. To figure out how many /48 blocks are in an IPv6 /16, =power(2,128-16)/power(2,128-48), 4.3 billion. There are also 4.3 billion individual addresses in IPv4.

Look for network properties or network settings. That might mean clicking on the Wi-Fi icon.

That will tell you your exact IP address (maybe both your IPv4 address and your IPv6 address). But it might be a private IPv4 address. If you want to see your public IP address, you can go to a page like www.arin.net where at the top left they’ll tell you what public IP address.

4,294,967,296.  There are 2 to the 32^nd power possible addresses in IPv4. However, many of them are reserved for special uses (224.0.0.0 and up), leaving  3,758,096,384 possible addresses. Some of those are reserved for private IP addresses, leaving 3,740,205,056. Some of those are reserved for other special uses (local addressing, documentation, and so on), but there are about 3.7 million public IPv4 addresses.

Almost all of those addresses have been assigned to somebody, somewhere. If you need IPv4 addresses, you’ll need to go to https://IPv4.Global/auctions to get them.

You go to IPv4.Global and register to buy addresses.

Once registered, you can either bid on an auction, or “buy now” for a set price. When you win, you receive an invoice to pay, and your money is held in escrow until the addresses are yours. Then you open a ticket with your RIR (Regional Address Registry, one of ARIN, RIPE, APNIC, LACNIC, AFRINIC) requesting those addresses be transferred to you (the seller does this too). In some regions, you have to show your address plan for how you’ll use the addresses, and this plan may need to be signed and notarized by a corporate officer. When the RIR has checked out you and the seller, they update their database, and the addresses are yours!

RIPE NCC (Réseaux IP Européens Network Coordination Centre) is the Regional Internet Registry serving Europe and the Middle East. They are the registry for Internet Protocol addresses for that region; they have the official record of what organizations hold what IP addresses.

If you need RIPE IP addresses, go to IPv4.Global and sign up to buy as much as you need.