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

       ip-netns - process network namespace management

       ip [ OPTIONS ] netns  { COMMAND | help }

       ip netns [ list ]

       ip netns add NETNSNAME

       ip [-all] netns del [ NETNSNAME ]

       ip netns set NETNSNAME NETNSID

       ip netns identify [ PID ]

       ip netns pids NETNSNAME

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

       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 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) sys‐
       tem 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 configura‐
       tion 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

       ip netns exec automates handling of this configuration, file convention for network namespace unaware applica‐
       tions, 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 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.  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 possi‐
              ble 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 names‐
              pace 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 appear‐
              ing 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 names‐
              pace 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 - list network namespace ids (nsid)

              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


       Original Manpage by Eric W. Biederman

iproute2                                             16 Jan 2013                                          IP-NETNS(8)