OpenStack Networking provides routing and NAT capabilities through the use of IP forwarding, iptables, and network namespaces. Each network namespace has its own routing table, interfaces, and iptables processes that provide filtering and network address translation. By leveraging network namespaces to separate networks, there is no need to worry about overlapping subnets between networks created by users. Configuring a router within Neutron enables instances to interact and communicate with outside networks or other networks in the cloud.

More information on routing within OpenStack can be found in Chapter 10, Creating Standalone Routers with Neutron, Chapter 11, Router Redundancy Using VRRP, and Chapter 12, Distributed Virtual Routers.