1IP-NETNS(8) Linux IP-NETNS(8)
2
6 ip-netns - process network namespace management
7
9 ip [ OPTIONS ] netns { COMMAND | help }
10 ip netns [ list ]
12 ip netns add NETNSNAME
14 ip netns attach NETNSNAME PID
16 ip [-all] netns del [ NETNSNAME ]
18 ip netns set NETNSNAME NETNSID
20 NETNSID := auto | POSITIVE-INT
22 ip netns identify [ PID ]
24 ip netns pids NETNSNAME
26 ip [-all] netns exec [ NETNSNAME ] command...
28 ip netns monitor
30 ip netns list-id [ target-nsid POSITIVE-INT ] [ nsid POSITIVE-INT ]
32
35 A network namespace is logically another copy of the network stack,
36 with its own routes, firewall rules, and network devices.
37 By default a process inherits its network namespace from its parent.
39 Initially all the processes share the same default network namespace
40 from the init process.
41 By convention a named network namespace is an object at
43 /var/run/netns/NAME that can be opened. The file descriptor resulting
44 from opening /var/run/netns/NAME refers to the specified network names‐
45 pace. Holding that file descriptor open keeps the network namespace
46 alive. The file descriptor can be used with the setns(2) system call to
47 change the network namespace associated with a task.
48 For applications that are aware of network namespaces, the convention
50 is to look for global network configuration files first in
51 /etc/netns/NAME/ then in /etc/. For example, if you want a different
52 version of /etc/resolv.conf for a network namespace used to isolate
53 your vpn you would name it /etc/netns/myvpn/resolv.conf.
54 ip netns exec automates handling of this configuration, file convention
56 for network namespace unaware applications, by creating a mount names‐
57 pace and bind mounting all of the per network namespace configure files
58 into their traditional location in /etc.
59 ip netns list - show all of the named network namespaces
62 This command displays all of the network namespaces in
64 /var/run/netns
65 ip netns add NAME - create a new named network namespace
68 If NAME is available in /var/run/netns/ this command creates a
70 new network namespace and assigns NAME.
71 ip netns attach NAME PID - create a new named network namespace
74 If NAME is available in /var/run/netns/ this command attaches
76 the network namespace of the process PID to NAME as if it were
77 created with ip netns.
78 ip [-all] netns delete [ NAME ] - delete the name of a network names‐
81 pace(s)
82 If NAME is present in /var/run/netns it is umounted and the
84 mount point is removed. If this is the last user of the network
85 namespace the network namespace will be freed and all physical
86 devices will be moved to the default one, otherwise the network
87 namespace persists until it has no more users. ip netns delete
88 may fail if the mount point is in use in another mount names‐
89 pace.
90 If -all option was specified then all the network namespace
92 names will be removed.
93 It is possible to lose the physical device when it was moved to
95 netns and then this netns was deleted with a running process:
96 $ ip netns add net0
98 $ ip link set dev eth0 netns net0
99 $ ip netns exec net0 SOME_PROCESS_IN_BACKGROUND
100 $ ip netns del net0
101 and eth0 will appear in the default netns only after
103 SOME_PROCESS_IN_BACKGROUND will exit or will be killed. To pre‐
104 vent this the processes running in net0 should be killed before
105 deleting the netns:
106 $ ip netns pids net0 | xargs kill
108 $ ip netns del net0
109 ip netns set NAME NETNSID - assign an id to a peer network namespace
112 This command assigns a id to a peer network namespace. This id
114 is valid only in the current network namespace. If the keyword
115 "auto" is specified an available nsid will be chosen. This id
116 will be used by the kernel in some netlink messages. If no id is
117 assigned when the kernel needs it, it will be automatically
118 assigned by the kernel. Once it is assigned, it's not possible
119 to change it.
120 ip netns identify [PID] - Report network namespaces names for process
123 This command walks through /var/run/netns and finds all the net‐
125 work namespace names for network namespace of the specified
126 process, if PID is not specified then the current process will
127 be used.
128 ip netns pids NAME - Report processes in the named network namespace
131 This command walks through proc and finds all of the process who
133 have the named network namespace as their primary network names‐
134 pace.
135 ip [-all] netns exec [ NAME ] cmd ... - Run cmd in the named network
138 namespace
139 This command allows applications that are network namespace
141 unaware to be run in something other than the default network
142 namespace with all of the configuration for the specified net‐
143 work namespace appearing in the customary global locations. A
144 network namespace and bind mounts are used to move files from
145 their network namespace specific location to their default loca‐
146 tions without affecting other processes.
147 If -all option was specified then cmd will be executed syn‐
149 chronously on the each named network namespace even if cmd fails
150 on some of them. Network namespace name is printed on each cmd
151 executing.
152 ip netns monitor - Report as network namespace names are added and
155 deleted
156 This command watches network namespace name addition and dele‐
158 tion events and prints a line for each event it sees.
159 ip netns list-id [target-nsid POSITIVE-INT] [nsid POSITIVE-INT] - list
162 network namespace ids (nsid)
163 Network namespace ids are used to identify a peer network names‐
165 pace. This command displays nsids of the current network names‐
166 pace and provides the corresponding iproute2 netns name (from
167 /var/run/netns) if any.
168 The target-nsid option enables to display nsids of the specified
170 network namespace instead of the current network namespace. This
171 target-nsid is a nsid from the current network namespace.
172 The nsid option enables to display only this nsid. It is a nsid
174 from the current network namespace. In combination with the tar‐
175 get-nsid option, it enables to convert a specific nsid from the
176 current network namespace to a nsid of the target-nsid network
177 namespace.
178
181 ip netns list
182 Shows the list of current named network namespaces
183 ip netns add vpn
185 Creates a network namespace and names it vpn
186 ip netns exec vpn ip link set lo up
188 Bring up the loopback interface in the vpn network namespace.
189 ip netns add foo
191 ip netns add bar
192 ip netns set foo 12
193 ip netns set bar 13
194 ip -n foo netns set foo 22
195 ip -n foo netns set bar 23
196 ip -n bar netns set foo 32
197 ip -n bar netns set bar 33
198 ip netns list-id target-nsid 12
199 Shows the list of nsids from the network namespace foo.
200 ip netns list-id target-nsid 12 nsid 13
201 Get nsid of bar from the network namespace foo (result is 23).
202
205 ip(8)
206
209 Original Manpage by Eric W. Biederman
210 Manpage revised by Nicolas Dichtel <nicolas.dichtel@6wind.com>
211iproute2 16 Jan 2013 IP-NETNS(8)