Address Resolution in IPv6

The ND protocol resolves IPv6 addresses to MAC addresses. This is typically a straightforward process. For example, in unicast global IPv6 addresses the 64-bit host portion of the IPv6 address is derived from the MAC address of the network adapter in the first place.

The resolution of host names to IPv6 addresses is accomplished through DNS (apart from link-local addresses that are not stored by DNS and resolve automatically). The procedure is the same as for IPv4 address resolution with the computer name and IPv6 address pair being stored in a AAAA (quad-A) DNS resource record, which is equivalent to an A or host record for IPv4. Reverse DNS lookup that returns a computer name for an IPv6 address is implemented by a pointer (PTR) DNS resource record that is referred to the IPv6 reverse lookup zone (or tree) ipv6.arpa, which is the equivalent of the in-addr.arpa reverse lookup zone in IPv4.

Creating an ipv6.arpa reverse lookup zone is a complex procedure that involves splitting the IPv6 address into 4-bit nibbles and entering these in reverse order. This is beyond the scope of the 70-680 examination.

In peer-to-peer environments where DNS is not available (for example, ad hoc networks), the Peer Name Resolution Protocol (PNRP) provides dynamic name registration and name resolution. PNRP can apply peer names to the machine or to individual applications and services on the machine. A peer name resolution includes an address, port, and possibly an extended payload. Peer names can be published as secured (protected) or unsecured (unprotected). PNRP uses public key cryptography to protect secure peer names against spoofing.