Sending emails over Ipv6

Hi

I would like to know how I can send emails over an IPv6 address.

Our hosting provides Ipv6 addresses and our mail server is already pointed to an A record (Ipv4) as well as an AAAA record (IPv6)

While doing some rounds of testing, I found that one of the emails that landed in Gmail was sent from the Ip6 address instead of the Ip4 one, but this doesn't happen always. And in Yahoo and Hotmail, it's the IP4 that's always the sending IP

The primary NS of our domain is pointed to the IP6 address.

I would like to know, how I can always make the outgoing emails originate from the Ip6 address.

Would it help if I delete the A record for our mail server and keep the AAAA record live (sorry if it's a dumb question)

Kindly advise


Thanks

IPv4/IPv6 is just the transport method utilized, and is not necessarily directly related to the IP address reported. If the sending machine and the receiving machine both reside on an IPv6 network, IPv6 addresses will be utilized and reported. If the sending machine and the receiving machine both reside on an IPv4 network, IPv4 addresses will be utilized and reported. But if either machine is utilizing a Tunnel Broker to bridge from one network to the other, things get a little confusing as a Tunnel Broker resides on both networks. It is the responsibility of the receiving server to add the originating sender's IP address to the email header. IPv6 is not universally implemented yet, so it is somewhat of a toss up as to what gets reported when it comes from a Tunnel Broker?

J.A. Coutts

Addendum: For example, Google (who is a strong supporter of IPv6) reports MX records for google.com as:
aspmx.l.google.com [173.194.79.27]
alt1.aspmx.l.google.com [209.85.225.26]
alt2.aspmx.l.google.com [74.125.45.26]
alt3.aspmx.l.google.com [173.194.76.26]
alt4.aspmx.l.google.com [173.194.73.27]
but no AAAA records for any of them

To find the IPv6 server, you have to use ipv6.google.com, which reports an MX of:
ipv6.l.google.com with no A record
and a AAAA record of [2001:4860:8005:000:000:000:000:067]