Learn how Cloudflare supports IPv6 traffic by default and the features Cloudflare recommends if your origin web server or application software does not support IPv6 traffic.
By default, Cloudflare provides free IPv6 support to all domains without requiring additional configuration or hardware. If your origin web server is not compatible with IPv6, Cloudflare allows toggling IPv6 Compatibility to Off. Alternatively, if clients connect to your Cloudflare-proxied domain via IPv6 but the origin web server uses older software that only understands IPv4 formatted IP addresses, use Cloudflare’s Pseudo IPv4 feature mentioned below.
Disable Cloudflare’s IPv6 Compatibility
If your hosting provider supports IPv6 for your origin web server, Cloudflare’s IPv6 Compatibility allows you to proxy IPv6 connections through Cloudflare's global network when proxying AAAA DNS records through Cloudflare.
Domains on Enterprise plans are allowed to toggle IPv6 within the UI:
- Login to your Cloudflare account.
- Select the appropriate domain.
- Click the Cloudflare Network app.
- Toggle IPv6 Compatibility Off or On.
Enable Pseudo IPv4
Some older origin analytics and fraud detection software expect IP addresses in an IPv4 format and do not support IPv6 addresses. Therefore, to support migration to IPv6, Cloudflare provides an IPv6 to IPv4 translation service available for all Cloudflare domains: Pseudo IPv4.
Pseudo IPv4 uses Class E IPv4 address space to provide as many unique IPv4 addresses corresponding to IPv6 addresses as possible.
- Example Class E IPv4 address: 240.16.0.1
- Example IPv6 address: 2400:cb00:f00d:dead:beef:1111:2222:3333
There are three options for Pseudo IPv4:
- Off - Default.
- Add Header - Cloudflare automatically adds the Cf-Pseudo-IPv4 headerwith a Class E IPv4 address hashed from the original IPv6 address.
- Overwrite Headers - Cloudflare overwrites the existing Cf-Connecting-IP and X-Forwarded-For headers with a Pseudo IPv4 address while preserving the real IPv6 address in a Cf-Connecting-IPv6 header.
Troubleshoot an IPv6 network issue
Provide the following information to Cloudflare Support if you experience issues with IPv6 connectivity:
- a traceroute that demonstrates the IPv6 connection issues,
- the Cloudflare data center serving your request when the IPv6 issues occur, and
- confirmation of whether disabling IPv6 Compatibility via the Cloudflare Network app resolves the issue.