1. ref

https://docs.iredmail.org/install.iredmail.on.debian.ubuntu.html
https://github.com/iredmail/iRedMail


Domain-based Message Authentication, Reporting, and Conformance (DMARC)
    https://datatracker.ietf.org/doc/html/rfc7489
Setup DNS records for your iRedMail server (A, PTR, MX, SPF, DKIM, DMARC)
    https://docs.iredmail.org/setup.dns.html

ubuntu 22.04
4 GB
Port 25 is required by mail server, but many ISPs block it by default.

2.1 prepare

sudo apt-get install -y gzip dialog
sudo vim /etc/hosts
sudo hostnamectl set-hostname mx.aisoit.com

2.1.2 prepare outbound port

25
587
110

995
143
993

2.1.3 prepare dns

mx.aisoit.com 113.149.218.254

2.1.4 prepare ssl

sudo snap install --classic certbot
sudo certbot certonly --webroot -w /var/www/html -d mx.aisoit.com
    Certificate is saved at: /etc/letsencrypt/live/mx.aisoit.com/fullchain.pem
    Key is saved at:         /etc/letsencrypt/live/mx.aisoit.com/privkey.pem

2.2 install

    tar xf iRedMail-1.6.7.tar.gz
    cd iRedMail-1.6.7
    bash iRedMail.sh

2.2.2 setup password

for mysql , and for postman

2.2.3 ssl config error