dr@mail:~ $ cat /etc/apt/apt.conf.d/50unattended-upgrades
Unattended-Upgrade::Origins-Pattern {
        "origin=Debian,codename=${distro_codename},label=Debian-Security";
};
Unattended-Upgrade::Package-Blacklist {
};

##</code><code>##

dr@mail:~ $ cat /etc/hosts
127.0.0.1       localhost mail
::1             localhost ip6-localhost ip6-loopback
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters

127.0.1.1       mail

##</code><code>##

dr@mail:~ $ sudo cat /etc/aliases
[sudo] password for dr:
# See man 5 aliases for format
#postmaster:    root
postmaster:    dr
root:          dr