The Closed Resolver Project

IP address spoofing has been a well-known security issue for a long time. It enables potential attackers to change their genuine IP addresses and become untraceable. The most efficient way to fight this problem is to perform packet filtering at the network edge, also known as Source Address Validation (SAV). Together with our partners from Université Grenoble Alpes we evaluate the SAV deployment of inbound traffic by sending DNS A requests to local resolvers on behalf of other hosts of tested networks. Not only we check filtering policies, but also reveal closed resolvers, not seen from outside otherwise.

Are you vulnerable?

Our partners from Université Grenoble Alpes periodically scan the whole routable IPv4 address space and a targeted list of IPv6 addresses to identify vulnerable networks. If you want to test your own network, please contact us.