I have now experienced this twice. The first time it happened, I chose to use the opportunity to change hosts since I had been wanting to for a while and I did not troubleshoot to the degree I typically do.
Right now, something is preventing our public IP from our ISP from connecting to any services on the MIAB server. I suspect it’s Fail2Ban.
It’s a bad day to spend much time on it right now, but I can confirm that I CAN access server (ssh, ftp, mail client, etc…) when I am running through a VPN or on a network other than home wired/wifi. This, of course, gives me a different IP that isn’t being blocked.
Any ideas why our IP would get blocked under a normal access scenario?
Do software updates/upgrades overwrite Fail2Ban configs and possibly remove whitelisted IPs?
What is the best config for Fail2Ban/MIAB to prevent this or keep our home network whitelisted?
As I mentioned, I haven’t got time this morning to properly troubleshoot or inspect logs - I’m making a best guess based on the behavior. And since I’m not a full time sysadmin I’d like input from people smarter than me.
MIAB is only running email for my family and my media production company so traffic should not be an issue, nor should failed logins.
Server is not appearing on any blacklists, and I do not suspect a breach at this time.