What is IPv4?

How IPv4 works

An IPv4 address is a 32-bit number, conventionally written as four decimal octets from 0 to 255 separated by dots — 198.51.100.24, for example. The leading bits identify the network and the remaining bits identify hosts within it, with the split expressed as a CIDR prefix length such as /24. Routers forward packets by matching the destination against the longest prefix they know.

The address space allows about 4.3 billion values, and sizable chunks are reserved for private networks, loopback, and multicast. Demand outgrew that supply long ago: the central pool was exhausted in the early 2010s, and regional registries have since run down their reserves. New addresses now come from reclamation, leasing, and a transfer market where blocks change hands for real money.

The internet responded by stretching what exists. NAT lets whole households share one address, carrier-grade NAT lets thousands of subscribers share one, and dual-stack deployments run IPv4 and IPv6 side by side during a transition that has taken decades.

Why IPv4 matters for proxies and scraping

Most websites and APIs are reachable over IPv4, and a meaningful share are reachable only over IPv4, so any proxy or scraping setup needs IPv4 exits for full target coverage. Scarcity also shapes economics: clean consumer IPv4 addresses are a finite resource, which is a large part of why residential and mobile proxy access costs more than plentiful alternatives.

Reputation systems track IPv4 addresses individually and by block, so an address's history — spam listings, abuse reports, prior automation — follows it. IPv6 offers a vastly larger and cheaper address space, but it only helps against targets that accept IPv6 connections; ProxyOmega's IPv6 plan, for instance, provides datacenter IPv6 threads suited to IPv6-capable targets.

Practical notes and common misconceptions

A common misconception is that IPv6 has replaced IPv4. Adoption has grown for years, but the web remains dual-stack, and crawl targets skew heavily toward IPv4 — confirm a target publishes AAAA records and actually serves IPv6 before committing to IPv6-only infrastructure.

Exhaustion also does not mean addresses disappeared. Blocks are constantly reassigned and leased, which is why an address's owning network and reputation can change over time, and why private ranges like 10.0.0.0/8 appear in every office and home network without conflicting on the public internet.