I asked that question in the nextcloud forum and [the letsencrypt forum], but it seems debian-related.
My domain is: bardhome.de
I ran this command: certbot renew bardhome.de
It produced this output:
Code: Alles auswählen
[ letsencrypt ] (Fri Mar 5 21:08:39 CET 2021)
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator webroot, Installer None
Renewing an existing certificate
Performing the following challenges:
http-01 challenge for bardhome.de 1
Using the webroot path /var/www/nextcloud for all unmatched domains.
Waiting for verification...
Cleaning up challenges
Failed authorization procedure. bardhome.de 1 (http-01): urn:ietf:params:acme:error:connection :: The server could not connect to the client to verify the domain :: Fetching http://bardhome.de/.well-known/acme-challenge/TO5r8JDwRFKyLGQsE5oUqPgRcDZiMcQxd7BxdSROVGE: Connection refused
Code: Alles auswählen
simon@debian-simon:~$ sudo ifconfig
[sudo] Passwort für simon:
docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.17.0.1 netmask 255.255.0.0 broadcast 172.17.255.255
ether 02:42:3e:ea:51:45 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.103.40 netmask 255.255.255.0 broadcast 192.168.103.255
ether 70:85:c2:85:93:9f txqueuelen 1000 (Ethernet)
RX packets 30027 bytes 20395989 (19.4 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 27003 bytes 8660314 (8.2 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Lokale Schleife)
RX packets 255891 bytes 56749269 (54.1 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 255891 bytes 56749269 (54.1 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lxdbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 10.203.243.1 netmask 255.255.255.0 broadcast 0.0.0.0
inet6 fd42:cdf5:fbdc:77f1::1 prefixlen 64 scopeid 0x0<global>
ether 00:16:3e:66:6a:33 txqueuelen 1000 (Ethernet)
RX packets 24 bytes 2844 (2.7 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 580 bytes 85272 (83.2 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
wlan0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether c6:a8:3c:f4:4c:77 txqueuelen 1000 (Ethernet)
RX packets 8 bytes 1848 (1.8 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 65 bytes 14707 (14.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
netstat gives me
Code: Alles auswählen
simon@debian-simon:~$ sudo netstat -tulpn
[sudo] Passwort für simon:
Aktive Internetverbindungen (Nur Server)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 2589/proftpd: (acce
tcp 0 0 10.203.243.1:53 0.0.0.0:* LISTEN 1776/dnsmasq
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 826/sshd
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 652/cupsd
tcp 0 0 0.0.0.0:1880 0.0.0.0:* LISTEN 4824/node-red
tcp 0 0 0.0.0.0:8088 0.0.0.0:* LISTEN 2452/asterisk
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 3560/exim4
tcp 0 0 0.0.0.0:1883 0.0.0.0:* LISTEN 4589/io.sonoff.0
tcp 0 0 127.0.0.1:5348 0.0.0.0:* LISTEN 871/turnserver
tcp 0 0 127.0.0.1:5348 0.0.0.0:* LISTEN 871/turnserver
tcp 0 0 127.0.0.1:5348 0.0.0.0:* LISTEN 871/turnserver
tcp 0 0 127.0.0.1:5348 0.0.0.0:* LISTEN 871/turnserver
tcp 0 0 127.0.0.1:9000 0.0.0.0:* LISTEN 1022/iobroker.js-co
tcp 0 0 127.0.0.1:9001 0.0.0.0:* LISTEN 1022/iobroker.js-co
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 4623/mysqld
tcp 0 0 0.0.0.0:4559 0.0.0.0:* LISTEN 2824/hfaxd
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/init
tcp 0 0 0.0.0.0:8084 0.0.0.0:* LISTEN 733/mono
tcp6 0 0 fd42:cdf5:fbdc:77f1::53 :::* LISTEN 1776/dnsmasq
tcp6 0 0 ::1:3350 :::* LISTEN 866/xrdp-sesman
tcp6 0 0 :::22 :::* LISTEN 826/sshd
tcp6 0 0 ::1:631 :::* LISTEN 652/cupsd
tcp6 0 0 :::25 :::* LISTEN 3560/exim4
tcp6 0 0 :::4443 :::* LISTEN 1030/apache2
tcp6 0 0 :::443 :::* LISTEN 1030/apache2
tcp6 0 0 :::3389 :::* LISTEN 927/xrdp
tcp6 0 0 :::8040 :::* LISTEN 1030/apache2
tcp6 0 0 :::5038 :::* LISTEN 2452/asterisk
tcp6 0 0 :::111 :::* LISTEN 1/init
tcp6 0 0 :::80 :::* LISTEN 1030/apache2
tcp6 0 0 :::8081 :::* LISTEN 1537/io.admin.0
udp 0 0 10.203.243.1:53 0.0.0.0:* 1776/dnsmasq
udp 0 0 0.0.0.0:67 0.0.0.0:* 1776/dnsmasq
udp 0 0 0.0.0.0:68 0.0.0.0:* 708/dhcpcd
udp 0 0 0.0.0.0:111 0.0.0.0:* 1/init
udp 0 0 0.0.0.0:53421 0.0.0.0:* 4537/io.mihome-vacu
udp 0 0 0.0.0.0:4569 0.0.0.0:* 2452/asterisk
udp 0 0 0.0.0.0:4570 0.0.0.0:* 2780/iaxmodem
udp 0 0 0.0.0.0:631 0.0.0.0:* 721/cups-browsed
udp 0 0 0.0.0.0:37519 0.0.0.0:* 2452/asterisk
udp 0 0 0.0.0.0:5070 0.0.0.0:* 2452/asterisk
udp 0 0 127.0.0.1:5348 0.0.0.0:* 871/turnserver
udp 0 0 127.0.0.1:5348 0.0.0.0:* 871/turnserver
udp 0 0 127.0.0.1:5348 0.0.0.0:* 871/turnserver
udp 0 0 127.0.0.1:5348 0.0.0.0:* 871/turnserver
udp 0 0 0.0.0.0:5353 0.0.0.0:* 647/avahi-daemon: r
udp 0 0 0.0.0.0:2727 0.0.0.0:* 2452/asterisk
udp 0 0 0.0.0.0:52228 0.0.0.0:* 647/avahi-daemon: r
udp6 0 0 fd42:cdf5:fbdc:77f1::53 :::* 1776/dnsmasq
udp6 0 0 :::111 :::* 1/init
udp6 0 0 :::547 :::* 1776/dnsmasq
udp6 0 0 :::5353 :::* 647/avahi-daemon: r
udp6 0 0 :::47044 :::* 2452/asterisk
udp6 0 0 :::59675 :::* 6206/skypeforl
udp6 0 0 :::43829 :::* 647/avahi-daemon: r
I can reach the nextcloud instance locally via the local IP adress without any issues.