[$] Should distributors disable IPv4-mapped IPv6?

By all accounts, the Internet's transition to IPv6 has been a slow affair.In recent years, though, perhaps inspired by the exhaustion of the IPv4address space, IPv6 usage has been on therise. There is a corresponding interest in ensuring that applicationswork with both IPv4 and IPv6. But, as a recent discussion on the OpenBSDmailing list has highlighted, a mechanism designed to ease the transition to anIPv6 network may also make the net less secure - and Linux distributionsmay be configured insecurely by default.