network_namespaces - overview of Linux network namespaces
Network namespaces provide isolation of the system resources associated with
networking: network devices, IPv4 and IPv6 protocol stacks, IP routing tables,
firewall rules, the
/proc/net directory (which is a symbolic link to
/proc/PID/net), the
/sys/class/net directory, various files
under
/proc/sys/net, port numbers (sockets), and so on. In addition,
network namespaces isolate the UNIX domain abstract socket namespace (see
unix(7)).
A physical network device can live in exactly one network namespace. When a
network namespace is freed (i.e., when the last process in the namespace
terminates), its physical network devices are moved back to the initial
network namespace (not to the parent of the process).
A virtual network (
veth(4)) device pair provides a pipe-like abstraction
that can be used to create tunnels between network namespaces, and can be used
to create a bridge to a physical network device in another namespace. When a
namespace is freed, the
veth(4) devices that it contains are destroyed.
Use of network namespaces requires a kernel that is configured with the
CONFIG_NET_NS option.
nsenter(1),
unshare(1),
clone(2),
veth(4),
proc(5),
sysfs(5),
namespaces(7),
user_namespaces(7),
brctl(8),
ip(8),
ip-address(8),
ip-link(8),
ip-netns(8),
iptables(8),
ovs-vsctl(8)