Dovecot邮件服务器的正确安装方法
apt remove dovecot-core
dpkg -P dovecot-core
sudo apt install dovecot-imapd dovecot-pop3d
参考https://help.ubuntu.com/lts/serverguide/dovecot-server.html
apt remove postfix
dpkg -P postfix
apt install postfix
vi /etc/postfix/main.cf
local_recipient_maps =
luser_relay = user@localhost
service postfix restart