ip-netns - process network namespace management
ip netns add NETNSNAME
ip [-all] netns del
ip netns set NETNSNAME NETNSID
ip netns identify
ip netns pids NETNSNAME
ip [-all] netns exec
ip netns monitor
ip netns list-id
A network namespace is logically another copy of the network stack, with its own
routes, firewall rules, and network devices.
By default a process inherits its network namespace from its parent. Initially
all the processes share the same default network namespace from the init
By convention a named network namespace is an object at
NAME that can be opened. The file descriptor resulting
from opening /var/run/netns/
NAME refers to the specified network
namespace. Holding that file descriptor open keeps the network namespace
alive. The file descriptor can be used with the setns(2)
system call to
change the network namespace associated with a task.
For applications that are aware of network namespaces, the convention is to look
for global network configuration files first in /etc/netns/
then in /etc/
. For example, if you want a different version of
for a network namespace used to isolate your vpn you
would name it /etc/netns/myvpn/resolv.conf.
ip netns exec
automates handling of this configuration, file convention
for network namespace unaware applications, by creating a mount namespace and
bind mounting all of the per network namespace configure files into their
traditional location in /etc.
- ip netns list - show all of the named network
This command displays all of the network namespaces in /var/run/netns
- ip netns add NAME - create a new named network
If NAME is available in /var/run/netns/ this command creates a new network
namespace and assigns NAME.
- ip [-all] netns delete [ NAME ] - delete the name of a
If NAME is present in /var/run/netns it is umounted and the mount point is
removed. If this is the last user of the network namespace the network
namespace will be freed and all physical devices will be moved to the
default one, otherwise the network namespace persists until it has no more
users. ip netns delete may fail if the mount point is in use in another
If -all option was specified then all the network namespace names
will be removed.
It is possible to lose the physical device when it was moved to netns and
then this netns was deleted with a running process:
$ ip netns add net0
$ ip link set dev eth0 netns net0
$ ip netns exec net0
$ ip netns del net0
and eth0 will appear in the default netns only
after SOME_PROCESS_IN_BACKGROUND will exit or will be killed. To prevent this
the processes running in net0 should be killed before deleting the netns:
$ ip netns pids net0 | xargs kill
$ ip netns del net0
- ip netns set NAME NETNSID - assign an id to a peer
This command assigns a id to a peer network namespace. This id is valid only
in the current network namespace. If the keyword "auto" is
specified an available nsid will be chosen. This id will be used by the
kernel in some netlink messages. If no id is assigned when the kernel
needs it, it will be automatically assigned by the kernel. Once it is
assigned, it's not possible to change it.
- ip netns identify [PID] - Report network namespaces
names for process
This command walks through /var/run/netns and finds all the network
namespace names for network namespace of the specified process, if PID is
not specified then the current process will be used.
- ip netns pids NAME - Report processes in the named
This command walks through proc and finds all of the process who have the
named network namespace as their primary network namespace.
- ip [-all] netns exec [ NAME ] cmd ... - Run cmd in the
named network namespace
This command allows applications that are network namespace unaware to be
run in something other than the default network namespace with all of the
configuration for the specified network namespace appearing in the
customary global locations. A network namespace and bind mounts are used
to move files from their network namespace specific location to their
default locations without affecting other processes.
If -all option was specified then cmd will be executed
synchronously on the each named network namespace even if cmd fails
on some of them. Network namespace name is printed on each cmd
- ip netns monitor - Report as network namespace names are
added and deleted
This command watches network namespace name addition and deletion events and
prints a line for each event it sees.
- ip netns list-id - list network namespace ids
Network namespace ids are used to identify a peer network namespace. This
command displays nsid of the current network namespace and provides the
corresponding iproute2 netns name (from /var/run/netns) if any.
ip netns list
Shows the list of current named network
ip netns add vpn
Creates a network namespace and names it
ip netns exec vpn ip link set lo up
Bring up the loopback interface in the vpn
Original Manpage by Eric W. Biederman