If the Hetzner server was replaced which includes the network card or motherboard,but not the disks, you need to update the networking configuration and firewall to reflect the new interface name. Use the Hetzner rescue console and mount the partition e.g.

mount /dev/md2 /mnt

Update the interface name in /etc/network/interfaces

root@rescue /mnt # cat etc/network/interfaces
### Hetzner Online GmbH installimage

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback
iface lo inet6 loopback

auto enp41s0
iface enp41s0 inet static
  address 157.90.212.174
  netmask 255.255.255.192
  gateway 157.90.212.129
  # route 157.90.212.128/26 via 157.90.212.129
  up route add -net 157.90.212.128 netmask 255.255.255.192 gw 157.90.212.129 dev enp41s0

iface enp41s0 inet6 static
  address 2a01:4f8:252:19d1::2
  netmask 64
  gateway fe80::1

Replace the enp41s0 with the new name, which you can get by running

udevadm test-builtin net_id /sys/class/net/eth0 | grep '^ID_NET_NAME_PATH'.

Don't forget the update firewall. In case of shorewall update the /etc/shorewall/interfaces file. Then reboot the server.

• Debian GNU/Linux 10 (buster)
• shorewall 5.2.4.5
• Hetzner rescue system used in August 2022

• Create RAID 5 from 4 disks with encryption on Hetzner

• https://docs.hetzner.com/robot/dedicated-server/general-information/system-adjustments-after-server-replacement