I have Mail-in-a-Box running on a Linode VPS. Got assigned an IPv6 /64 subnet so I can meet Spamhaus’s requirements to get unblocked, and followed https://www.linode.com/docs/networking/linode-network/linux-static-ip-configuration/#ubuntu-18-04 to make the system use one of the new addresses. However, Mail-in-a-Box is still using the old IPv6 address, and even shows it when running mailinabox, while ip address shows both.
There are red status checks, but they are all related to DNS for domains for which I’m using external DNS. There are no red status checks for the main domain and the box’s subdomain.
I’m not really sure whether this is a Linode problem, a Mail-in-a-Box problem, or if I just screwed up somewhere. Regardless, any help would be appreciated.
I did all the above some time in the past, but recently discovered that the configuration had at some point reverted to Linode’s SLAAC IPv6 address for my Linode instance (when my email started getting rejected as spam again). After several tries, the following procedure seems to have resulted in a persistent change to the new IPv6 address:
Edit /etc/systemd/network/05-eth0.network as described in this specific answer: IPv6 setup trouble | Linode Questions
In particular, I could not get this to work without the [IPv6AcceptRA] section at the bottom.
Edit /etc/mailinabox.conf and change both the public and private IPv6 addresses listed therein to the new one.
Reboot the instance.
Run the usual curl -s https://mailinabox.email/setup.sh | sudo -E bash MiaB setup. Watch carefully that in fact it now reports your new IPv6 address.
Reboot the instance one more time to get the DNS server running on the new IPv6 address.
That should do it. Hope this turns out to be helpful for others.