Comprehensive IPv6 Migration Case Study of the Dewu App

According to the NetInfo China report released on January 28, 2022, by the end of December 2021, 87 Chinese apps had IPv6 traffic share exceeding 65%. The Dewu App achieved an IPv6 density of 94.60%, ranking first in the inspection. This article shares the full‑scene IPv6 transformation experience of the Dewu App for reference.

IPv6 provides a massive address space and leaves ample room for protocol innovation, making it the core direction for the next‑generation Internet worldwide and the only correct path for China’s Internet upgrade.

For an internet company with hundreds of millions of monthly active users, IPv6 migration is a complex undertaking. This article outlines the overall project experience of Dewu App’s IPv6 overhaul.

Current IPv6 support status

iOS : Since WWDC 2015 Apple announced iOS 9 support for pure IPv6. From iOS 12.1 onward, the system fully supports dual‑stack IPv4/IPv6.

Android : Android 8.0 and later fully support dual‑stack; Android apps are the main focus of the migration.

Web site : Most company homepages are IPv6‑reachable only at the homepage level; deeper links are not yet IPv6‑enabled.

Public cloud : Major ISPs and public‑cloud providers (e.g., Alibaba Cloud) already offer IPv6 access for end users.

Architecture overview

The complete App network architecture is illustrated below:

Request flow

Parsing layer : HttpDNS for domain resolution with anti‑hijack, local DNS from carriers, and a dual‑active module for IP‑level high‑availability.

Server layer (business APIs) : User IP is forwarded via X‑Forwarded‑For to the business gateway; big‑data event reporting via Flink/Kafka; static assets served by third‑party CDN; core services (main site, risk control, order) accessed through HTTPS and security gateway; H5 front‑end mainly for banners and growth scenes.

Client/Player layer : Android/iOS clients integrate third‑party SDKs (HttpDNS, big‑data, captcha, etc.); live streaming uses custom push SDK and Agora; player SDK includes ffmpeg and other open‑source libraries.

Transformation plan

Server side: all systems handling user IP must recognize, store, and be compatible with IPv6; gateway must forward IPv6 via X‑Forwarded‑For; risk‑control rules must allow IPv6 traffic; monitoring must track success rate, error rate, latency for IPv6 users; IP‑to‑geo services must support IPv6.

Client side: enable IPv4+IPv6 dual‑stack with IPv6 preference; implement downgrade to IPv4 when IPv6 connection fails; support gray‑scale rollout based on user/version.

Migration steps

Business investigation : Identify all domain names used by Android modules (e.g., via Charles); ensure SDKs and network libraries support IPv6; include H5 and mini‑program pages that use IP logic.

Business testing : Regression testing of IPv4 flows, internal user experience testing, and verification of IPv6 rollback mechanisms.

App rollout : Release gray‑scale test builds, verify IPv6 switch is on, then gradually increase IPv6 traffic in production.

Monitoring : Real‑time monitoring of success rate, latency, and order metrics; ability to rollback instantly.

Key cases

CDN : Enable IPv6 on commercial CDN nodes; monitor IPv6 bandwidth share and 5xx error rates; verify ISP‑wide IPv6 support.

Live streaming : Recompile ffmpeg with IPv6 support; adjust SDK logic to prefer IPv6 URLs; after migration, IPv6 density rose from single digits to over 90%.

Big‑data reporting : Ensure all pipelines (data warehouse, anti‑fraud, recommendation, etc.) can handle IPv6 addresses without breaking downstream logic.

Main site domain : Deploy dual‑stack load balancers and gateways; use Proxy Protocol for L4 to preserve X‑Forwarded‑For; after gray‑scale verification, shift production traffic to IPv6.

Client migration : Implement IPv6 preference logic, local‑DNS fallback, and dual‑active IP list handling; conduct extensive gray‑scale testing to avoid failures in pure IPv4 environments.

Overall, Dewu App’s full‑scene IPv6 transformation achieved the top ranking among 200 surveyed apps, demonstrating a successful, repeatable migration methodology.