IPv4 vs IPv6: What's the Difference?

The headline difference is size. IPv4's 32-bit space caps out at ~4.3 billion addresses, which the internet ran out of years ago. IPv6's 128-bit space is effectively limitless. That scarcity is why IPv4 leans heavily on NAT (Network Address Translation — many devices sharing one public address, like an office full of phones behind a single front-desk number), whereas IPv6 can give every device its own unique public address. The notation differs too: IPv4 is four dotted decimal octets, IPv6 is eight hex groups separated by colons (with :: as shorthand for long runs of zeros). IPv6 also simplified the packet header and builds in features — like stateless autoconfiguration (devices set up their own address automatically) and mandatory support for IPsec (built-in encryption for traffic) — that were optional add-ons in IPv4.

IPv6 was created for one main reason: to solve IPv4 address exhaustion. As billions of phones, servers, and IoT devices (everyday internet-connected gadgets) came online, the 4.3-billion IPv4 ceiling became a hard limit — kept alive only by NAT and a secondary market where IPv4 address blocks are bought and sold. IPv6's enormous space removes that constraint. Adoption is gradual because the two protocols can't talk to each other directly. So the internet runs both side by side (called dual-stack) during the long transition, which means most networks still need working IPv4 alongside IPv6.

For scraping, the practical question isn't which protocol is 'better' — it's which one your target sites trust. Many sites and anti-bot vendors still treat IPv4 residential addresses (real home internet connections) as the most human-looking. Large blocks of IPv6 are easier to fingerprint and ban in bulk: a single ISP can hand out a whole /64 (a huge range of addresses) to one customer, so anti-bot systems can block a suspicious IPv6 range wholesale. Datacenter IPv6 in particular is often distrusted. The upshot: for protected targets, residential proxies on IPv4 are usually the most reliable choice, while IPv6 can be fine for IPv6-only sites or high-volume, low-sensitivity crawling. If you're seeing blocks that line up with IP version, switching to trusted IPv4 residential addresses is the first thing to try.