Continuing from this Static IPv6 post I discovered that my outbound emails were still sometimes going from the wrong IPv6 address and therefore being flagged as Spam. I had thought using a different sub-domain for that IP and then using these:
myhostname = ducks0.heysi.co.uk smtp_helo_name = ducks0.heysi.co.uk
would be enough, but nope. The secret is explictly setting the IP address for smtp:
smtp_bind_address6 = 2a01:7e00:e000:35b::1
Hopefully I finally have it working properly now. Life sure would be easier if I wasn’t bothered about IPv6 and hosting my own email.
I don’t know why, but it feels weird including actual IP addresses and domain names in a blog post even though they are very much public