Thanks again for the great product, I cannot say it enough. I like the Nextcloud integration as well, we were even able to easily phase out Dropbox-like services.
We are running on Linode, and in order to resolve the “Linode issue” they assigned us a /64 range. I enabled the range on our system and configured this as our “Public IPv6” address. I successfully reconfigured mailinabox.
However, even with this change, some remote mailservers still block us with a new error, according to them the PRIVATE IP is not allowed to send mail for that domain (SPF record error). I assumed (wrongly?) the private IP is not used for outgoing connections. How does this work?
I tried to configure the private IP address to this range as well, but was unable to. It came back with the original private IP.
I have changed the smtp bind address in the configuration:
root@box:/etc/postfix# grep ‘::’ /etc/postfix/main.cf
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
smtp_bind_address6=2a01:7e00:xxxx:yyyy::
This seams to control the address postfix uses for outgoing IPv6 SMTP traffic, I am now able to send email to these addresses.
It does not seam to affect the listen address:
root@box:~# netstat -anp|grep ‘:25’|grep LISTEN
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 1259/master
tcp6 0 0 :::25 :::* LISTEN 1259/master
This worked after reboot, and I assume this will remain working on every reboot, except when MIAB setup is reran (to, for example, upgrade it). I am not sure if certbot renewal will break this as well, but I guess I will know within 90 days.
Also I have opened a ticket with Linode, perhaps they have an idea how to resolve this.