What Is an IPv4 Address and Why It Still Matters
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An IPv4 address is a 32-bit number that identifies a device or connection point on a network, written as four values from 0 to 255 separated by dots, for example 203.0.113.25. The whole IPv4 space holds about 4.3 billion addresses, and the free pool ran out more than a decade ago, which turned IPv4 into a resource with a market price. IPv6 exists, but most websites and apps still rely on IPv4, so IPv4 proxies remain the most widely used kind. This guide explains how an IPv4 address is built, how to read subnet notation, why addresses are scarce and how all of that affects renting a proxy.
How an IPv4 address is built
Each IPv4 address is 32 bits long, split into four 8-bit groups called octets. Each octet ranges from 0 to 255, which is why addresses look like 192.168.1.10. Computers only see a string of 32 ones and zeros; the dotted decimal form is for humans.
Every address has a network part, which says which range it belongs to, and a host part, which picks a specific device in that range. A subnet mask or CIDR suffix marks where one ends and the other begins.
| Element | Example | Meaning |
|---|---|---|
| Address | 203.0.113.25 | Identifies one connection point |
| Octets | 203 / 0 / 113 / 25 | Four 8-bit groups, 0 to 255 each |
| CIDR notation | 203.0.113.0/24 | First 24 bits are the network |
| Equivalent mask | 255.255.255.0 | Another way to write /24 |
| Addresses in a /24 | 256 | .0 to .255, usually 254 usable |
Reading /24, /16 and subnets
The number after the slash is how many leading bits belong to the network. A /24 fixes the first three octets and leaves the last one free, giving 256 addresses. A /16 fixes two octets and contains 65,536 addresses. The bigger the number, the smaller the range.
This matters for proxy users because many platforms notice when several IPs sit in the same range. If you run multiple accounts, read subnets and multiple accounts for practical ways to spread your IPs.
Special IPv4 ranges you will meet
- Private ranges
10.0.0.0/8,172.16.0.0/12,192.168.0.0/16: used inside local networks and never routed on the internet. See public vs private IP. - Carrier-grade NAT
100.64.0.0/10: used by providers that put many subscribers behind one public IP. - Loopback
127.0.0.0/8: points back to your own machine;127.0.0.1is localhost. - Link-local
169.254.0.0/16: self-assigned when a device gets no address from the router, usually a sign of a network problem. - Documentation ranges such as
203.0.113.0/24: reserved for examples and never assigned to real hosts.
Why IPv4 ran out
Thirty-two bits allow roughly 4.3 billion addresses before reserved ranges are removed. That looked generous when the internet was designed, but not with billions of phones, computers, servers and smart devices. IANA, the global coordinator, handed out its last blocks to the regional registries in 2011, and the regions then ran out of ordinary new allocations one after another.
Since then, organisations that need more IPv4 buy or lease it from current holders, and providers stretch supply with NAT and carrier-grade NAT. A dedicated public IPv4 address has become genuinely valuable, which is part of what you pay for with a private IPv4 proxy.
IPv4 vs IPv6 for proxies
IPv6 uses 128-bit addresses and is practically unlimited, yet not every website, app or network fully supports it. An IPv6 proxy only reaches IPv6-enabled destinations, while an IPv4 proxy reaches almost everything. Because IPv6 is so plentiful, many platforms also judge whole IPv6 blocks rather than single addresses.
Our IPv4 vs IPv6 proxy comparison covers the details. VinaProxy currently sells IPv4 and static ISP proxies; IPv6 is paused.
What you get when you rent an IPv4 proxy
A dedicated IPv4 proxy is a public IPv4 address assigned to you on a proxy server. Every request through it reaches websites with that address. At VinaProxy proxies are delivered as ip:port:user:pass, use HTTP/HTTPS and authenticate with a username and password.
- Dedicated: each IP goes to one customer, so its reputation depends on how you use it.
- Static: the IP stays the same for the rental period, and renewing on the dashboard keeps it. See static vs dynamic IP.
- Seven countries: Vietnam, the US, Japan, South Korea, Singapore, the UK and Hong Kong, for example Vietnam IPv4 proxies.
- Check on delivery: paste your list into the proxy checker to confirm each IP works and shows the expected country.
Frequently asked questions
How many numbers are in an IPv4 address?
Four numbers from 0 to 255 separated by dots, 32 bits in total.
How many IPv4 addresses exist?
In theory 2 to the power of 32, about 4.3 billion. A large share is reserved for private networks, multicast and special uses, so fewer are routable on the internet.
How do I find my IPv4 address?
Your public address is shown on a what-is-my-IP page. Your local address is shown by ipconfig on Windows or ip addr on Linux.
Why do IPv4 proxies cost more than IPv6?
IPv4 is scarce and has to be bought or leased, while IPv6 is abundant. Current prices for each type are on the pricing page.
Do IPv4 proxies work with every website?
Practically every website supports IPv4, so compatibility is the widest. Whether a site accepts a particular IP still depends on its type, reputation and how it is used.
Rent dedicated IPv4 in seven countries
One customer per IP, static for the whole rental period, unlimited bandwidth and automatic activation, usually within minutes.
See IPv4 plans