RFC 2328, "OSPF Version 2", April 1998Source of RFC: ospf (rtg)
Errata ID: 3734
Reported By: Ramakrishna DTV
Date Reported: 2013-09-23
Verifier Name: Stewart Bryant
Date Verified: 2013-10-10
Section 8.2 says:
The AuType specified in the packet must match the AuType specified for the associated area.
It should say:
The AuType specified in the packet must match the AuType specified for the associated interface.
In OSPFv2, authentication is configured per interface and not per area.
Appendix D clarifies this: "The authentication type is configurable on a per-interface
(or equivalently, on a per-network/subnet) basis."