The IPv6 specification allows IPv6 Header Chains of an arbitrary size. The specification also allows options that can@ in turn@ extend each of the headers. In those scenarios in which the IPv6 Header Chain or options are unusually long and packets are fragmented@ or scenarios in which the fragment size is very small@ the First Fragment of a packet may fail to include the entire IPv6 Header Chain. This document discusses the interoperability and security problems of such traffic@ and updates RFC 2460 such that the First Fragment of a packet is required to contain the entire IPv6 Header Chain.