I'm running debian buster, and let exim4 deliver for localhost mail from apt-listchanges. this works but I get the error
alex@Taomon:~$ LANG=C
alex@Taomon:~$ systemctl status exim4
* exim4.service - LSB: exim Mail Transport Agent
Loaded: loaded (/etc/init.d/exim4; generated)
Active: active (running) since Mon 2021-11-29 10:51:40 CET; 5h 36min ago
Docs: man:systemd-sysv-generator(8)
Process: 1299 ExecStart=/etc/init.d/exim4 start (code=exited, status=0/SUCCESS)
Tasks: 1 (limit: 4340)
Memory: 5.7M
CGroup: /system.slice/exim4.service
`-1571 /usr/sbin/exim4 -bd -q30m
Nov 29 10:51:40 Taomon systemd[1]: Starting LSB: exim Mail Transport Agent...
Nov 29 10:51:40 Taomon exim4[1299]: Starting MTA:hostname --fqdn did not return a fully qualified name, dc_minimaldns will not
Nov 29 10:51:40 Taomon exim4[1299]: work. Please fix your /etc/hosts setup.
Nov 29 10:51:40 Taomon exim4[1299]: exim4.
Nov 29 10:51:40 Taomon systemd[1]: Started LSB: exim Mail Transport Agent.
alex@Taomon:~$
I read over the years some sides but never understood to solve it. I tried more than once
dpkg-reconfigure exim4-config
some I hope relevant infos
alex@Taomon:~$ cat /etc/hostname
Taomon
alex@Taomon:~$
root@Taomon:~# hostnamectl status
Static hostname: Taomon
Icon name: computer-laptop
Chassis: laptop
Machine ID: 84876d350fa0dd8b520fd47e0000000b
Boot ID: 0144c780c7d747de92e1fbb41b1b506e
Operating System: Debian GNU/Linux 10 (buster)
Kernel: Linux 4.19.0-18-amd64
Architecture: x86-64
root@Taomon:~#
Next to long for here Exim in address testing mode
Note exim delivers my mail correct. But the error makes me nervous. Almost forgot
root@Taomon:~# cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 Taomon
#PS4 einbinden
#172.16.0.2 PS4
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
#fe00::0 ip6-localnet
#ff00::0 ip6-mcastprefix
#ff02::1 ip6-allnodes
#ff02::2 ip6-allrouters
root@Taomon:~#