That's really interesting. I've been considering moving back to my own mail server from gmail for a long time but have been worried about the security issues.
This is one more thing pushing me in that direction.
This is one more thing pushing me in that direction.
After the typical host hardening stuff (which isn't much work with modern OS defaults), I have configured SPF, DKIM, DMARC policy, opportunistic TLS for server-to-server, and mandatory TLS for IMAP client connections.
From a data privacy perspective, I know that nobody is mining the contents of my mailbox (except the messages I send to Gmail, etc. users!), and my server is not a high-value target for compromise. (Yes, DigitalOcean could snoop on my non-GPG-encrypted messages if they wanted. I guess I could migrate the server back to my own hardware.) I also encourage friends to use GPG, though this is orthogonal to one's choice of email host.
For clients I use Thunderbird on desktop and K-9 Mail on Android. Mobile push via IMAP IDLE works out of the box. (I also run a CalDAV/CardDAV server to sync contacts/calendar/todo across devices, but that is technically separate.)
Overall I'm really happy with the arrangement. The only annoyance was having my messages to Gmail users consistently marked as spam, but after doing everything suggested by mail-tester.com, I think I'm making it through most of the time.
I've been hosting my own email for about 3 years now, in an even worse-for-my-domain-reputation way: by using SRS.
Basically any email that arrives at my domain gets forwarded to my Gmail account.
And because I use SRS, it will re-write the envelope so it's something like hash-original_domain=user@mydomain.
Yet I've never had a problem with my emails getting marked as spam.
Actionable advice:
- setup DMARC and use something like dmarcian[1] so you have a pretty dashboard of your DMARC reports (otherwise you have to find some tool that will read the XML and aggregate the reports).
- use mxtoolbox to verify your IPs aren't blacklisted, you aren't an open relay, etc.
- if you have enough email traffic (not likely if you're using it for personal email only), signup for Google's Postmaster[3]
Ask if you need any help.
I know someone who does his own mail and does less than me (e.g. no SRS), and yet he doesn't have problems and thinks I'm doing something wrong...
My best hypothesis is that Google doesn't like the network that my server is in (Hetzner, various neighbours in the network are listed on a couple blacklists). When I find the time I'll set up a server with a different provider and see if it improves things. Other hypotheses are the software used (buddy uses OpenBSD and its mail server instead of Linux and QPSMTPD/Qmail+patches, perhaps they care about software headers or are doing OS fingerprinting), the fact that I'm using a fallback server on another continent (US), network timings, and plain noise (perhaps they use some kinds of machine learning that have persistent low-level irregularities).
PS. yes I'm not doing DMARC yet, but neither does my buddy.
I wonder why.
Having an honest reason to belong to a minority that is on average very dishonest is one of the worst things that can happen to you.
This is a real dilemma, not just with spam filtering.
I bet that's not the whole story. There was a reason they were lazy in the first place, but I bet there's another reason why they stay lazy. Punishing decentralization is a great way to get more users, after all: sent from gmail? works. Sent from little provider? Doesn't work.
The only way out of this I see right now is the generalization of the Freedom Box. Though even then, one would need to run protests to be able to send email from home. Between ISP wide firewalls, interdictions on home servers (by contract with some ISP), or the blacklisting of all residential IPs (Hotmail), it will take a lot of collective action before we can send mail from home again.
I very much doubt that Google sees decentralization as a major threat to Gmail at this point.
Since Snowden, people know they are being spied on. The only reason so many of them still use Gmail is because they don't know how not to. Give them a little box that's as usable as Gmail, and they will use it.
While I agree decentralization is hardly a threat to Gmail right now, it could be, and I don't see them taking any step to make it even more threatening.
Perhaps a spammer with a new server could gain Gmail's trust by passing genuine-looking correspondence, but this would stop working as soon as they start to send bulk messages.
Seems to me that tuning Gmail's filters to recognize and trust small-volume email servers would not be difficult or time-consuming.
However, I fear if Google were to try harder, spammers would also jump on that opportunity. It's easier to mimic the patterns of a small legit SMTP server than to pose as one of a few big well established email providers with known IP ranges. They could potentially use millions of compromised PCs, each sending spam in low volumes mixed with non-spam traffic.
https://github.com/Kozea/Radicale/issues/266 https://github.com/Kozea/Radicale/issues/388
I'm told that using a dedicated HTTP + WSGI server solves this, just haven't done the work yet.
Moreover, systemd has a OnFailure directive that activates other units when the process exits uncleanly. Upstart has a similar directive. With a more classical approach, `respawn' is a utility that can invoke and maintain the running status of a process launched from System V Init, or you could use the regarded inittab solution.
I've seen answers to questions similar to this on StackOverflow respond with scripts that are nothing more than a while(true) loop that checks to see if a PID exists in languages ranging from Bourne shell to Python and NodeJS. This is the wrong way to do it, especially the Node one. Lets take a language intended to be used inside a web browser client and slap it onto a server to be used for process monitoring. I'm sure it does a fine job with it's while loop, but we're hitting copper pipe with a tire iron wondering why our lightbulb isn't turning on here.
Started using it after Owncloud/Nextcloud broke their ldap auth.
But now I might try it again some time.
If you’re lucky, the IP in question hasn’t previously been used to spam & by very slowly ramping up your email rate Google will eventually decide that you’re probably OK. Getting this right appears to be something of a black art however :(
It is certainly still valuable work to audit the software used for the mailserver. But the challenges lie elsewhere. The biggest chunks are configuration issues and - if you have users that aren't very security savvy - stolen passwords and subsequent abuse of mail accounts for spam.
This is where having a mail server with a sane configuration file comes handy. OpenSMTPd is simply awesome in that regard. Plus, it too was recently audited and vulnerabilities fixed so it should be secure.
OpenSMTPd + Dovecot makes for an awesome combination for a mail server.
I wouldn't worry too much about running many services. They all run as their own unprivileged users. (Of course chroots or even jails/containers would be better.)
I just recently set it up to use TLS on port 993. It was easy to do.