Looking at this I would assume that the default networking provided by Docker is NAT Network, but Docker likes to call it as Bridge Network. So the containers are not visible to the world except for HOST. And any machine on the internet/intranet can't access the Containers except through port forwarding provided by the HOST. For accessing the internet these containers rely on SNAT provided by HOST. Similarly, a second container can get an IP 172.17.0.23. When an image is run on the HOST (whose IP from above is 152.50.60.21) using Dockers default networking (which it calls as Bridge Network), the new container can get an IP (say) 172.17.0.13 from the network - 172.16.0.0/12 (at least on my env). VMWare Doc's reference: Understanding Common Networking Configurations But the VM's can access the outer world/internet/intranet though SNAT provided by HOST i.e the IP's of VM's are never exposed to the outer world.

So two VM's spinning up on the host and connected through NAT Network can have IP's 10.0.3.3 and 10.0.3.6īeing on the NAT Network the VM's are not visible to the outer world beyond the host i.e the VM's are not reachable to the outer world (except with DNAT/Port Forwarding configuration on the Host). Though, if am right, any CIDR is fine.) Safely, this new NAT Network being created on host and accessible only on the host can have CIDR 10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16 (or any subnet of these networks). And VMWare can accept any valid CIDR (to not complicate things I will refer to the private reserved blocks only. NAT Network - NAT is a separate network from the network the host is connected to. Any machine on the internet can reach the VM's and the VM's can reach the internet directly (of course if the HOST network is connected to internet). The Bridge Network connects the VM's on to the same network the host is connected to.

Similarly, a second VM can have an IP 152.50.60.32 if this IP is free.

So if IP 152.50.60.30 is free, then VM can bind to this IP. Say the Host IP is some random 152.50.60.21 and the network CIDR is 152.50.60.0/24.īridge Network - Any VM connected through this interface can have any free IP on the network the host is connected to. TL DR - Why does Docker call it's default networking as Bridge Networking when it seems to be a lot like NAT Network.ġ) VMWare or VirtualBox handles networking for virtual machines.

Vmware vs virtualbox at same time