A home NAS (HP microserver) via rsync, and from there I use duplicity to upload to google cloud storage (multi-regional coldline). The latter is ~€ 10 per 1 TiB.
I like having a copy at hand for ease and speed of recovery, but if I had to choose only one, I’d go for the cloud one since it’s off-site.
Food for thought because my default position has been “don’t run your own mail server” until now.
The “proof of work” take is interesting. Although I’ve never bothered with SPF or DKIM and don’t have deliverability problems. I might look at DKIM one day (but SPF is, imho, a total waste of time).
I’m not sure if the “programming” tag is appropriate
For what is worth, my experience is that SPF configured with “-all” does work pretty effectively, and is much more useful these days than it was in the past. It’s also quite easy to set up.
Googling “proof of work email spam” actually revealed that solving this problem originally with HashCash is what has led to the big cryptocurrency revolution!
Reminded me of https://wiki.recompile.se/wiki/Mandos, the meain difference seems that kxd uses x509 certificates while mandos utilizes gpg?
Yes, there are many differences, but at a high level I agree that’s the main difference.
It seems like today is a day for SMTP servers in the news! This one seems interesting mainly for being “easy to configure, hard to misconfigure in ways that are harmful or insecure”.
Thanks! If you want to know anything specific or have any questions about that, feel free to ask :)