|reply to probuddha |
Re: Sending emails over Ipv6
It may also be related to the "Happy Eyeballs" RFC for IPv6:
This is non-deterministic in that is simply chooses the "fastest" transport in a dynamic way. As long as both transports are working well, one will see an apparently random mix.
An application that uses a Happy Eyeballs algorithm checks both IPv4 and IPv6 connectivity (with a preference for IPv6) and uses the first connection that is returned. The addresses are often chosen from the DNS with a round-robin algorithm. Implementations of Happy Eyeballs stacks exist in Google's Chrome web browser, Firefox version 13, and Mac OS X Lion (although Lion uses the fastest connection, rather than preferring IPv6). Happy Eyeball testing was part of World IPv6 Day in 2011.