Support for IPv6 on SPF and account migrations
Currently cPanel doesn't handle IPv6 addresses on SPF, so...
- If you migrate an account with SPF enabled to a server with IPv6: Google, Microsoft and Yahoo will get your e-mails thru IPv6 and thus SPF will fail or soft-fail (-all vs ~all).
- If you migrate an account with SPF enabled with +ip6 added manually, the IPv6 address won't be rewritten and thus e-mails will fail.
- If your server have an IPv6 address and you (or your customer) enable SPF that IPv6 address won't be added to your TXT entry at the DNS. It also can't be added because there's no input for it, you have to manually edit the DNS zone to add it.
Workarounds for now
-Setup an IPv6 MX so that the +mx automatically includes that IP address on all SPFs, this will also allow that all e-mail coming from Gmail / Microsoft / Yahoo, can reach your servers thru IPv6. You'll have to manually edit it when migrating.
-Setup the +ip6 address on the SPF so that the SPF validates when sending e-mail thru it. You'll also have to manually edit it when migrating.
-Disable IPv6 on the server.