IP-NETNS(8)			     Linux			   IP-NETNS(8)

NAME
       ip-netns - process network namespace management

SYNOPSIS
       ip [ OPTIONS ] netns  { COMMAND |  help }

       ip netns [ list ]

       ip netns add NETNSNAME

       ip netns attach NETNSNAME PID

       ip [-all] netns del [ NETNSNAME ]

       ip netns set NETNSNAME NETNSID

       NETNSID := auto | POSITIVE-INT

       ip netns identify [ PID ]

       ip netns pids NETNSNAME

       ip [-all] netns exec  [ NETNSNAME ] command...

       ip netns monitor

       ip netns list-id [ target-nsid POSITIVE-INT ] [ nsid POSITIVE-INT ]


DESCRIPTION
       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 process.

       By convention a named network namespace is an object at
       /var/run/netns/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/NAME/ then in /etc/.	For example, if you want a different
       version of /etc/resolv.conf 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 namespaces

	      This command displays all of the network namespaces in
	      /var/run/netns


       ip netns add NAME - create a new named network namespace

	      If NAME is available in /var/run/netns this command creates a
	      new network namespace and assigns NAME.


       ip netns attach NAME PID - assign a name to the network namespace of
       the process

	      If NAME is available in /var/run/netns this command attaches the
	      network namespace of the process PID to NAME as if it were
	      created with ip netns.


       ip [-all] netns delete [ NAME ] - delete the name of a network
       namespace(s)

	      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 mount
	      namespace.

	      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 SOME_PROCESS_IN_BACKGROUND
		 $ 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 network namespace

	      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 network namespace

	      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 executing.


       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 [target-nsid POSITIVE-INT] [nsid POSITIVE-INT] - list
       network namespace ids (nsid)

	      Network namespace ids are used to identify a peer network
	      namespace. This command displays nsids of the current network
	      namespace and provides the corresponding iproute2 netns name
	      (from /var/run/netns) if any.

	      The target-nsid option enables to display nsids of the specified
	      network namespace instead of the current network namespace. This
	      target-nsid is a nsid from the current network namespace.

	      The nsid option enables to display only this nsid. It is a nsid
	      from the current network namespace. In combination with the
	      target-nsid option, it enables to convert a specific nsid from
	      the current network namespace to a nsid of the target-nsid
	      network namespace.


EXAMPLES
       ip netns list
	      Shows the list of current named network namespaces

       ip netns add vpn
	      Creates a network namespace and names it vpn

       ip netns exec vpn ip link set lo up
	      Bring up the loopback interface in the vpn network namespace.

       ip netns add foo
       ip netns add bar
       ip netns set foo 12
       ip netns set bar 13
       ip -n foo netns set foo 22
       ip -n foo netns set bar 23
       ip -n bar netns set foo 32
       ip -n bar netns set bar 33
       ip netns list-id target-nsid 12
	      Shows the list of nsids from the network namespace foo.
       ip netns list-id target-nsid 12 nsid 13
	      Get nsid of bar from the network namespace foo (result is 23).


SEE ALSO
       ip(8)


AUTHOR
       Original Manpage by Eric W. Biederman
       Manpage revised by Nicolas Dichtel <nicolas.dichtel@6wind.com>

iproute2			  16 Jan 2013			   IP-NETNS(8)