IPv6 Source Addresses Considered Harmful

In this deliberately preposterous paper, we show that the inclusion of the source IP addresses in the IPv6 header is completely unnecessary and usually harmful. In particular, we show that whenever IPsec is used in conjunction with IPv6, we would do much better using the 128 bits that are currently wasted for the source address with something much more useful, such as passing randomly looking bits. Furthermore, we argue that the source addresses pose one of the worst privacy threats in the IPv6 architecture; simply leaving them out would be a clear improvement of privacy. Finally, we show how a simple destination option is better than the current practice for providing the source address in the rare cases where it is really needed.