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IPv6-Mostly on Campus#

LACNIC 46 digest Program Adjacent pick 19–22 October 2026

Slides Recording

Henri Alves de Godoy (UNICAMP)

Play the recording: IPv6-Mostly on Campus

  • Why: Measured, published evidence of what DHCP Option 108, PREF64, and CLAT actually do on a production campus — rare empirical data for anyone planning IPv6-mostly rollouts.
  • What: A pilot on the FCA-Unicamp campus Wi-Fi (2,524 undergraduates). Findings: Option 108 (RFC 8925) does not prevent or disable IPv4 — the client decides; PREF64 (RFC 8781) is necessary but not sufficient; automatic CLAT activation is strongly associated with the absence of native IPv4. macOS/iOS/Android have native CLAT; Linux needs clatd or maturing NetworkManager support; Windows 11 began rolling out CLAT in September 2026. Dual-stack devices still send traffic toward PREF64/NAT64 (DNS64, Happy Eyeballs effects). Net effect: IPv4 DHCP pool pressure drops, and residual IPv4 dependency becomes visible and measurable — consistent with draft-ietf-v6ops-6mops (v10, Sep 2026).
  • How: Standard tooling — radvd, Kea DHCPv4, BIND, Jool NAT64 (--pool6 64:ff9b::/96) — plus Python measurement scripts the authors published for download.
  • Where applicable: Campus/enterprise managed networks; the methodology and scripts are replicable anywhere. Framed as "map where IPv4 is still needed" rather than "eliminate IPv4."