docker run –dns 8.8.4.4 nicolaka/netshoot nslookup google.com – example of command using given dns to solve name (google.com in this case) to IP address, instead of default dns (usually it is host machine dns)

The scenarios to specify dns in Docker is :

• running containers in different environments using their own Domain Name Servers (dns)
• running containers in local intranet

To provide default value of dns /etc/docker/daemon.json file is used. Its contents in general has many settings, among which there is dns setting, where needed IP address can be set.

Docker Security

Levels of Security in Docker :

• Namespaces and cgroups (control groups) : not two or more containers can have the same namespace and container id