.\" Copyright (c) 2017 by Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.\"
.TH network_namespaces 7 2023-03-12 "Linux man-pages 6.04"
.SH NAME
network_namespaces \- overview of Linux network namespaces
.SH DESCRIPTION
Network namespaces provide isolation of the system resources associated
with networking: network devices, IPv4 and IPv6 protocol stacks,
IP routing tables, firewall rules, the
.I /proc/net
directory (which is a symbolic link to
.IR /proc/ pid /net ),
the
.I /sys/class/net
directory, various files under
.IR /proc/sys/net ,
port numbers (sockets), and so on.
In addition,
network namespaces isolate the UNIX domain abstract socket namespace (see
.BR unix (7)).
.PP
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 namespace of the parent of the process).
.PP
A virtual network
.RB ( 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
.BR veth (4)
devices that it contains are destroyed.
.PP
Use of network namespaces requires a kernel that is configured with the
.B CONFIG_NET_NS
option.
.\" FIXME .SH EXAMPLES
.SH SEE ALSO
.BR nsenter (1),
.BR unshare (1),
.BR clone (2),
.BR veth (4),
.BR proc (5),
.BR sysfs (5),
.BR namespaces (7),
.BR user_namespaces (7),
.BR brctl (8),
.BR ip (8),
.BR ip\-address (8),
.BR ip\-link (8),
.BR ip\-netns (8),
.BR iptables (8),
.BR ovs\-vsctl (8)