I know the adage that self-hosting email is hard. I use a third party smtp server to send emails for my Lemmy instance in order to guarantee delivery, for example.
However, other than potential uptime, what are the disadvantages to setting up self-hosted incoming email?
Incoming email is like 99% of my email usage. I’m happy to use a third party mail provider for outgoing email, but don’t see why I shouldn’t simply host incoming email myself.
Thank you <3
I don’t see anything wrong with self-hosting the receiving part. Especially with something like mailcow it shouldn’t be any more difficult than hosting anything else, provided you have backups in place and will be able to get the server up and running again within 24 hours to not lose any emails. Yes, spam may be an issue, but mailcow has useful defaults configured and it works okay-ish for me.
Btw, they also allow for configuring outbound relays quite easily. This allows for simpler configuration on the client-side. I have it set up so that all emails sent through mailcow will be forwarded to mailgun, for example.
Do you know if 24h is the typical timeout for re-trying to send an email. How about I put a traditional email provider as second priority in MX records in case my server goes down? That should work, right?
I think after a few hours the sending mail server will start notifying users of an undeliverable message but will still retry. But of course everyone can configure that themselves, so I don’t know exactly what is typical in this case. I personally wouldn’t want a downtime of more than 6 hours for my mailserver.
Yes, adding a second MX should work. Though I could imagine that this server will get some mails regardless, as there may sometimes be a temporary disruption for just a few seconds on your main mail server (network is funny), in which case the sending server will probably attempt to deliver to the second MX right away, instead of retrying the first one in a few minutes. So make sure you don’t miss any emails because you forget to check the second email provider.
The standard is to retry for 5 days before bouncing emails as undeliverable (and send a warning message that the email hasn’t yet been delivered after 4 hours). However, every server can configure it to be whatever they want, so there’s no guarantee.
You can’t just use any old provider as a secondary mx, you need a server which is configured to accept mail for your domain but not try and deliver it locally. It’s pretty simple to set up. The biggest issue is that you need the same spam protections on the secondary as on the primary, as spammers will send directly to the secondary to try and bypass spam protections.
Thank you, that makes sense. I think I might give it a try first with some non-critical domain to get a feeling for it.