A Secure, Flexible Framework for DNS Authentication in IPv6 Autoconfiguration

Abstract

The Domain Name System (DNS) is an essential part of the Internet on whose function many other protocols rely. One key DNS function is Dynamic Update, which allows hosts on the network to make updates to DNS records dynamically, without the need for restarting the DNS service. Unfortunately, this dynamic process does expose DNS servers to security issues. To address these issues two protocols were introduced: Transaction Signature (TSIG) and Domain Name System Security Extensions (DNSSEC). In Internet Protocol version 4 (IPv4) networks using these protocols eliminated security issues. In Internet Protocol version 6 (IPv6) however, there is an issue with the DNS authentication process when using the Stateless Address Auto Configuration (SLAAC) mechanism (new to IPv6, nonexistent in IPv4). This authentication issue occurs when a node wants to update its resource records on a DNS server, during the DNS update process, or when a client wants to authenticate a DNS resolver to ensure that the DNS response does not contain a spoofed source address or message. In this paper we propose the use of a new mechanism which makes use of asymmetric cryptography to establish a trust relationship with the DNS server. We also consider the use of the current security parameters used to generate IPv6 addresses in a secure manner, i.e. Secure Neighbor Discovery (SeND), for assuring clients and DNS servers that the one they are communicating with is the real owner of this IP address. Since we are extending the RDATA field within the TSIG protocol to accommodate these new security parameters, we will call this new mechanism the CGA-TSIG algorithm.