I have been using MIAB for several years now (v0.15) and it was running smooth (thanks for this great piece of software). But unfortunately, few months ago, it was suddenly impossible to receive email, but also to send emails (blocked using dbl.spamhaus.org).
I investigated on dbl.spamhaus.org and it seems that because my IP belongs to the blocks owned by OVH, it was black listed as all other IP (like 300.000 other IP, which sounds stupid). And dbl.spamhaus.org refused to remove my IP from their list unless I pay a service (around $10 per month if I remember well). I refused.
At that time, my MIAB version was a bit old, so I upgraded it and the problem disappeared.
Recently, I moved my MIAB into another proxmox host and problem started again.
Actually, I realized that my box is blocked (send & receive) each time I reboot (something I have to do more frequently and that I was not doing before).
To make it working smooth again, I just need to start MIAB install script !
(the well known : ‘curl -s https://mailinabox.email/setup.sh | sudo bash’)
FYI, my box IP is NOT blacklisted by dbl.spamhaus.org:
It is 18.104.22.168 and it is an IP Failover affected to my MIAB VM on my promox baremetal server.
Surprisingly, the blocking message do not report exactly my IP :
Service unavailable; Sender address [cfbcom at cobaltsolutions.info] blocked using dbl.spamhaus.org; Error: open resolver; DNSBL Error Code - Open/public resolver - The Spamhaus Project.
This IP seems to be host6.waw.cdns.ovh.net and belongs to OVH network (but I have no clue why it comes into this spamhaus error message from my MIAB).
I know that this blocking topic has been discussed few time in the forum.
Some of you were proposing to edit /etc/postfix/main.cf
But this is not a real fix for this issue, and I think there is a real bug here (turning the box into a blocked one by just rebooting is not right).
I also read things about DNS but I did not changed anything to my MIAB DNS config and I do not really know what to do.
I do not have the network skills to debug this, but if anyone has, I can give access to my box to understand better what’s going on… As we are more and more to have this issue.
(as a turn around, I try to no reboot my MIAB for now…)