Quotas

Now this is a feature that caused me quite some headache. But in the end it was pretty simple. Quotas are size limits for users. You can make sure that users do not waste infinite amounts of disk space but

Success stories

I would appreciate if you leave a comment here telling others if your mail server is running. Perhaps even a word about the purpose of the mail server and the number of users you have. That allows others to see

Blocking malware

My usual rant: I consider virus scanners snake oil. If anyone wants to seriously infect a computer by sending an infected attachment then virus scanners won’t help you. They are based on patterns of known malware and (if you are lucky)

Monitoring and backup

You have come a long way. Glad you made it. So many weird things complicated the journey that evolved from the very beginning of using email roughly 35 years ago. But before you take your much deserved break from these

Firewalling and brute force mitigation

So many bad guys everywhere. Paranoia you say? Well, take a look at your mail log. While I was preparing this guide I could barely follow it. The mail server I used for testing was by far not ready and

Managing users, aliases and domains

Maybe you already know what you have to do to create mail domains and mail users. After all I tried to explain the database schema in the section that dealt with preparing the database. But if that wasn’t clear enough

Prevent spoofing using DKIM

Email sender spoofing is the act of pretending to be in control of someone else’s email address. This is a common problem with phishing. Often scammers send emails with a sender address of something@paypal.com and hope that the recipient falls

Mail client auto-configuration

Have you ever worked with Thunderbird as a mail client? When you add a mail account you get a wizard like this: You click on Continue and Thunderbird tries to find out which parameters are needed to connect to your

DNS records

MX entries So now you have your working mail server. But how do other mail servers get to know you? The answer lies in the most important service on the internet: DNS. Assume that a mail server somewhere on the

Filtering out spam with rspamd

You have come a long way in this guide and your mail server is already fully functional. Now it’s time to deal with the dark side: spam. The amount of spam nowadays has been insane for many years. So we