Few weeks late to pitch in now but I can +1 docker-mailserver.

It has almost everything included and the configuration files are quite straightforward and flexible enough that you can drop little edits into the individual services if you need to tweak something.

My setup is very close to what you want: I use fetchmail to pull in from my old gmail and yahoo inboxes, I also have my own domain so I configured the MX records so that emails go straight to my server, with a fallback to my email provider (any mail that doesn't make it directly to my mailserver will still get pulled into my inbox with fetchmail when it comes back online).

Docker-mailserver allows you to set the SMTP of your instance to use your provider. This is important because it means that they do all the reputation stuff so that your emails work properly (and both my home ISP and my VPS provider don't do sending over pot 25 anyway).

So when I need to connect a new client (like Thunderbird) to my email I don't need to manually config anything as docker-mailserver has all the auto config messages so its really seamless. At the same time my risk is low because even if my sever is off my provider will still receive anything on my behalf. I can only send using the username I have paid for from my provider and switching between gmail and yahoo is not possible without rewriting configs and restarting services but its not something I want anyway. On the receiving side I can have any number of aliased usernames that will all be received by my server (but only when its on so i use them rarely and for disposable addresses).

Big downsides are:

• backups are now my problem as I don't keep duplicates.
• I route my traffic via a VPS+VPN to get a static public IP address - this was a headache to get all the little details just right but its stable now
• I have to host separately my own webmail, although I'm mostly using my phone with k-9 Mail and Thunderbird (I use roundcube)
• Getting server side filtering rules working was also annoying and so far I still have to add new rules through roundcube (there was a plugin for Thunderbird but I don't want to open the additional ports required)
• !!! Spam !!! Docker-mailserver has a great Rspamd default settings out the box so its actually fine but now I have to manage all the additional rules and its not super intuitive especially because I am doing all this just for myself (yay!) but the tools are clearly meant for managing a fleet of inboxes so everything takes me longer to figure out
• integrating contacts is not included and might be important for your experience (again I was able to add this as a plugin to roundcube ..... eventually)

Most of my complaints stem from the fact that I'm not very good at this but in the end it has been very satisfying to drop the occasional: "I host my own email BTW"

Good luck! Let us know how you get along!

you're welcome.

what i'ld suggest... a general rule that i like to always follow is to use a test system for everything new. but that does not need to be a full separate system every time.

lets say you have your mailbox and want to try getting new mails from it using fetchmail. first you can use uidl mechanisms to only fefch every mail once and besides that leave them all on the server, but i like it a bit more secure: create a second email adress/account at your mail providers service only for testing. thus you can do whatever you like to to test the mechanisms only without even touching your real inbox (maybe even fill it up with large emails and look how the system reacts, i once had an email account with a cheap provider that deadlocked the inboxes when full..). then when everything is as you want it, switch the account and password (or create another config file for fetchmail) and your're done. every change (not only fetchmail things) could go tested this way before going live with the changes. filtering could be done with procmail for example, but when the mda that is called by procmail somehow exits with success when the email really isn't delivered, then the email might get lost forever depending on the settings of course. so fiddling with new stuff always carries the risk of not fiddling correctly ;-)

have fun !