IPv6 just turned 30 and still hasn't taken over the world
IPv6 turns 30 with roughly half of global traffic now using it, yet IPv4 remains indispensable and many networks still run IPv4-only. Commenters highlight a split reality: mobile carriers, major ISPs and big cloud providers increasingly rely on IPv6, while enterprises, small ISPs and homelab users often avoid it due to perceived complexity, lack of skills, dynamic prefixes and limited business incentives to migrate. Much of the debate centers on whether NAT and private IPv4 space are “good enough,” how real IPv6’s privacy and security trade-offs are, and whether the protocol’s design and deployment model doomed it to coexist with IPv4 indefinitely rather than replace it.
Adoption: “Failed” vs “Everywhere”
- Thread splits between “IPv6 is a failure” and “IPv6 is already half the internet.”
- Several participants cite stats (Google, APNIC) and operational experience: ~50% of Google traffic, most mobile networks, many home ISPs and big clouds use IPv6 heavily, sometimes IPv6‑only with IPv4 via NAT64/464XLAT.
- Others note their own devices or ISPs have no IPv6, so they perceive it as dead; people conflate “I don’t see it” with “it isn’t used.”
Enterprise, VPNs, and Address Planning
- Many enterprises and data centers still run IPv4‑only inside, using RFC1918 (especially 10/8) plus NAT.
- Engineers describe real scaling problems: overlapping 10/8 ranges across business units, mergers, and inter‑company VPNs causing painful renumbering, async routing, and nested NAT.
- Some large orgs have exhausted public /8s and private space and are kludging with additional “reserved” ranges; IPv6 is seen as “distant aspiration.”
NAT, CGNAT, and Peer‑to‑Peer
- NAT is widely (mis)treated as a security feature and privacy layer; many home admins explicitly prefer “NAT as default-deny.”
- Others stress that security comes from firewalls, not translation, and that CGNAT breaks or complicates P2P, VoIP, gaming, and self‑hosting.
- Some see CGNAT as accidental privacy (many users per IPv4), others call it “the devil” and expect ISPs to monetize logs and IPv4 scarcity.
ISPs, Prefixes, and Practical Pain
- Experiences vary wildly: some ISPs give stable, generous prefixes (/56 or /48) and working PD; others offer no IPv6, only CGNAT, or dynamic /64s that change frequently.
- Dynamic IPv6 prefixes break self‑hosting and firewall rules; workarounds (ULA, dynamic DNS, NAT66) are considered clunky.
- A number of users report ISPs that once deployed IPv6 then quietly turned it off.
Complexity, Design Choices, and Alternatives
- Critics argue IPv6 suffers from “second‑system effect”: 128‑bit addresses, SLAAC, privacy extensions, multiple address types, and uneven DHCPv6 support (notably on Android) make it feel over‑engineered.
- Others say at layer 3 it’s simpler than IPv4 (fixed header, straightforward subnetting, plenty of space) and that most complexity is operator self‑inflicted.
- Long subthreads debate “IPv4+”: adding extra bits or options while keeping dotted‑quad semantics; defenders of IPv6 say any real extension would have required essentially the same dual‑stack migration.
Privacy, Security, and Centralization
- Some disable IPv6 entirely, fearing easier device‑level tracking and loss of “casual anonymity” from shared IPv4 and CGNAT.
- Counterpoint: both stacks are equally subpoena‑able, browser fingerprinting dominates tracking, and IPv6 privacy extensions randomize interface IDs.
- Several argue that lack of end‑to‑end reachability (NAT, CGNAT) helped push the ecosystem toward centralized cloud platforms and away from true peer‑to‑peer.