to change the password connect to the container and change the password

lxc exec <container-name> bash

you will be connected as root user, and changing the root password

lxc network edit lxdbr0

• using the cli

lxc network set lxdbr0 ipv4.address 10.1.11.1/24
lxc network set lxdbr0 ipv4.dhcp.ranges 172.31.18.100-172.31.18.200