Set the DNS server on Debian 11

Add dns-nameservers line in /etc/network/interfaces as below.

auto enp6s0
iface enp6s0 inet static
  bridge_ports enp6s0
  address 192.168.1.100
  netmask 255.255.255.0
  gateway 192.168.1.1
  dns-nameservers 192.168.1.254

Ref.: https://wiki.debian.org/NetworkConfiguration