IPv4 vs IPv6: What Is the Difference?
A short, practical comparison of IPv4 and IPv6: address format, why IPv6 exists, and what it means for everyday users and developers.
IPv4 has been the workhorse of the internet for decades. With only about 4.3 billion possible addresses, it ran out long ago. IPv6, with 340 undecillion addresses, was designed to remove that ceiling and modernize how the internet routes traffic.
Address format
IPv4 uses four numbers separated by dots, like 198.51.100.5. IPv6 uses eight groups of hexadecimal characters separated by colons, like 2001:0db8:85a3::8a2e:0370:7334. Leading zeros can be compressed.
Do I need to choose one?
For end users, no. Modern operating systems and browsers use whichever protocol is available, often both. If a site supports IPv6 and your connection does too, you may be reaching it over IPv6 without noticing.
Why developers care
Server software, firewalls, logging, and analytics must understand both. Geolocation databases for IPv6 are improving but still less precise than IPv4 in many regions.
常见问题
Is IPv6 faster than IPv4?
Not inherently. Performance depends on network conditions. IPv6 can avoid certain NAT-related overhead, but day-to-day differences are usually negligible.
Is IPv4 going away?
Not soon. IPv4 will coexist with IPv6 for many years through dual-stack networks and translation technologies.
相关内容
- What Is My IP Address? A Plain-English GuideA clear, non-technical explanation of what an IP address is, why websites can see it, and what it does — and does not — reveal about you.
- How IP Geolocation WorksA short technical overview of how IP addresses are mapped to physical locations, and why it is fundamentally probabilistic.
来源：ip-api 文档、区域互联网注册机构（ARIN、RIPE、APNIC、LACNIC、AFRINIC）以及 BGP 路由数据。