The Hitchhiker's Guide to IPv6: Don't Panic… We've Only Got 30 Minutes#

Nicole Wajer (Cisco)

• Why: Practical IPv6 operational hardening in the trenches — the kind of small failure modes (ACLs, neighbor discovery, wireless RA handling) that bite during dual-stack or IPv6-only rollouts. Relevant background for anyone running DC edge or enterprise access alongside the fabric.
• What: A war-story tour of IPv6 gotchas: IPv6 ACLs have implicit permits for ND-NS/ND-NA (so "tightening" an ACL can still break or unexpectedly pass neighbor discovery); a GUA-loss case caused by SSID jumping and stale neighbor cache; and a case where Windows + Cisco Secure Client stopped receiving unsolicited RAs, killing IPv6 after ~15 minutes until a bug fix shipped. Closes with an IPv4-to-IPv6-only migration path slide.
• How: Diagnosis via neighbor-cache state machines, RA/RS behavior on interface bounce, and Wireshark captures — emphasizing that IPv6 failure modes are control-plane (ND/RA) rather than the IPv4-style ARP debugging people reach for.
• Where applicable: General dual-stack/enterprise-wireless advice, not org-specific. Speaker is a Cisco evangelist and the war stories involve Cisco gear and Cisco Secure Client specifically, so some fixes are vendor-fix rather than technique; the diagnostic approach transfers anywhere.