Hi!
In preparation for the World IPv6 Launch, inbound (SMTP) email to the comcast.net domain was IPv6-enabled today, June 5, 2012, at 9:34 UTC. Roughly one minute later, at 9:35:30 UTC we received our first inbound email over IPv6 from 2001:4ba0:fff4:1c::2. That first bit of mail was spam, and was caught by our Cloudmark messaging anti-abuse platform (the sender attempted a range of standard spam tactics in subsequent connections).
In the past several hours we have of course seen other messages from a range of hosts, many of which were legitimate email so it wasn't just spam! ;-)
Since the Internet is of course more than just the web, we encourage others to start making non-HTTP services available via IPv6 as well.
Looking more closely... Is this still work in progress? ;; ANSWER SECTION: comcast.net. 358 IN MX 5 mx3.comcast.net. comcast.net. 358 IN MX 10 mx1.comcast.net. comcast.net. 358 IN MX 5 mx2.comcast.net. ;; ADDITIONAL SECTION: mx2.comcast.net. 6958 IN A 76.96.30.116 mx3.comcast.net. 358 IN A 68.87.26.147 mx1.comcast.net. 358 IN AAAA 2001:558:fe14:70::22 You are now only accepting IPv6 if all IPv4 fails? Or will AAAA records for mx2 and mx3 added later? Bye, Raymond.