Virtual Private Network (VPN) traffic leakages in dual-stack hosts/ networks

The information below is for an old version of the document
Document Type Expired Internet-Draft (opsec WG)
Author Fernando Gont 
Last updated 2013-06-15 (latest revision 2012-12-12)
Replaces draft-gont-opsec-vpn-leakages
Stream Internet Engineering Task Force (IETF)
Expired & archived
pdf htmlized bibtex
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Stream WG state WG Document
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IESG IESG state Expired
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


The subtle way in which the IPv6 and IPv4 protocols co-exist in typical networks, together with the lack of proper IPv6 support in popular Virtual Private Network (VPN) products, may inadvertently result in VPN traffic leaks. That is, traffic meant to be transferred over a VPN connection may leak out of such connection and be transferred in the clear on the local network. This document discusses some scenarios in which such VPN leakages may occur, either as a side effect of enabling IPv6 on a local network, or as a result of a deliberate attack from a local attacker. Additionally, it discusses possible mitigations for the aforementioned issue.


Fernando Gont (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)