A method, a computer program product, and a system are disclosed, which use OAuth2 to secure IPv6 Neighbor Discovery. The method including sending a Neighbor Discovery duplicate address detection (DAD) package from a client device on a communication network, the Neighbor Discovery DAD package having an authorization code for an OAuth2 token for access to an IPv6 network; receiving the Neighbor Discovery DAD package with the authorization code on an authorizing device, the authorizing device configured to issue OAuth2 tokens; issuing the OAuth2 token having an expiration to the client device for access to the IPv6 network; and allowing the client device to access the IPv6 network until the expiration of the OAuth2 token.