Hello,
I want to deploy a simple mail server so that it can be used for users to register themselves or reset passwords, etc.
Is there an easy one to deploy (in docker if possible) ?
You are asking for a world of pain here.
I wrote a blog some time ago why selfhosting email sucks
https://nx2.site/email-selfhosting
If you just want the email server for only you and your friends, or for internal messages, selfhosting email can be fun, but your main email should probably not be selfhosted.
If you do self host I suggest reading carefully the Gmail guidelines for mails. They are the leaders in the field and they dictate the level of security required.
DNS forward and reverse, DKIM, SPF, DMARC, ARC, DANE, bounce signature etc. Email is indeed a very complicated thing to host. I work on emails system all day and and I wouldn’t host my own mail.
Even worse I’m hoping email disappear and another technology takes it place. Emails are unreliable and outdated, they need to go.
As already mentioned several times, selfhosting a mail server is not recommended unless you’re particularly interested in hosting a mail server, but with that said, you might find this project interesting:
Please, just don’t. It’s pain in ass