# IPv6 Tunneling and Misconfiguration

> Detects network configurations that fail to apply security controls to IPv6, allowing bypass via IPv6 tunneling.

- Skill: `zakirkun/ipv6-tunneling-and-misconfiguration` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add zakirkun/ipv6-tunneling-and-misconfiguration`
- Raw SKILL.md: https://api.skillmd.com/api/skills/zakirkun/ipv6-tunneling-and-misconfiguration/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: zakirkun (https://skillmd.com/u/zakirkun)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/zakirkun/ipv6-tunneling-and-misconfiguration

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# IPv6 Tunneling and Misconfiguration

## Overview
Security controls applied only to IPv4 can be bypassed via IPv6:
- Firewalls blocking IPv4 but allowing all IPv6
- SSRF filters blocking `127.0.0.1` but not `::1` (IPv6 loopback)
- Rate limiters keyed on IPv4 that miss IPv6 addresses
- DNS rebinding via IPv6 link-local addresses

## Remediation
- Apply identical security rules to IPv4 and IPv6
- Block `::1` and IPv6 link-local ranges in SSRF filters
- Test security controls explicitly with IPv6 addresses