Interface Configuration and Management

This section discusses how to configure and manage network interfaces.

Cumulus Linux uses ifupdown2 to manage network interfaces, which is a new implementation of the Debian network interface manager ifupdown.

Basic Commands

Bring Up the Physical Connection to an Interface

To bring up the physical connection to an interface or apply changes to an existing interface, run the sudo ifup <interface> command. The following example command brings up the physical connection to swp1:

cumulus@switch:~$ sudo ifup swp1

To bring down the physical connection to a single interface, run the sudo ifdown <interface> command. The following example command brings down the physical connection to swp1:

cumulus@switch:~$ sudo ifdown swp1

The ifdown command always deletes logical interfaces after bringing them down. When you bring down the physical connection to an interface, it comes back up automatically after you reboot the switch or apply configuration changes with ifreload -a.

By default, ifupdown is quiet. Use the verbose option (-v) to show commands as they execute when you bring an interface down or up.

Bring Up an Interface Administratively

When you bring an interface up or down administratively (admin up or admin down), you bring down a port, bridge, or bond but not the physical connection for the port, bridge, or bond.

When you put an interface into an admin down state, the interface remains down after any future reboots or configuration changes with ifreload -a.

To put an interface into an admin down state:

cumulus@switch:~$ net add interface swp1 link down
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

These commands create the following configuration in the /etc/network/interfaces file:

auto swp1
iface swp1
    link-down yes

To bring the interface back up:

cumulus@switch:~$ net del interface swp1 link down
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

To put an interface into an admin down state:

cumulus@switch:~$ nv set interface swp1 link state down
cumulus@switch:~$ nv config apply

To bring the interface back up:

cumulus@switch:~$ nv set interface swp1 link state up
cumulus@switch:~$ nv config apply

To put an interface into an admin down state:

cumulus@switch:~$ sudo ifdown swp1 --admin-state

To bring the interface back up:

cumulus@switch:~$ sudo ifup swp1 --admin-state

For additional information on interface administrative state and physical state, refer to this knowledge base article.

Interface Classes

ifupdown2 enables you to group interfaces into separate classes. A class is a user-defined label that groups interfaces that share a common function (such as uplink, downlink or compute). You specify classes in the /etc/network/interfaces file.

The most common class is auto, which you configure like this:

auto swp1
iface swp1

You can add other classes using the allow prefix. For example, if you have multiple interfaces used for uplinks, you can define a class called uplinks:

auto swp1
allow-uplink swp1
iface swp1 inet static
    address 10.1.1.1/31

auto swp2
allow-uplink swp2
iface swp2 inet static
    address 10.1.1.3/31

This allows you to perform operations on only these interfaces using the --allow=uplinks option. You can still use the -a options because these interfaces are also in the auto class:

cumulus@switch:~$ sudo ifup --allow=uplinks
cumulus@switch:~$ sudo ifreload -a

If you are using Management VRF, you can use the special interface class called mgmt and put the management interface into that class. The management VRF must have an IPv6 address in addition to an IPv4 address to work correctly.

allow-mgmt eth0
iface eth0 inet dhcp
    vrf mgmt

allow-mgmt mgmt
iface mgmt
    address 127.0.0.1/8
    address ::1/128
    vrf-table auto

All ifupdown2 commands (ifup, ifdown, ifquery, ifreload) can take a class. Include the --allow=<class> option when you run the command. For example, to reload the configuration for the management interface described above, run:

cumulus@switch:~$ sudo ifreload --allow=mgmt

Use the -a option to bring up or down all interfaces with the common auto class in the /etc/network/interfaces file.

To administratively bring up all interfaces marked auto, run:

cumulus@switch:~$ sudo ifup -a

To administratively bring down all interfaces marked auto, run:

cumulus@switch:~$ sudo ifdown -a

To reload all network interfaces marked auto, use the ifreload command. This command is equivalent to running ifdown then ifup; however, ifreload skips unchanged configurations:

cumulus@switch:~$ sudo ifreload -a

Cumulus Linux checks syntax by default. As a precaution, apply configurations only if the syntax check passes. Use the following compound command:

cumulus@switch:~$ sudo bash -c "ifreload -s -a && ifreload -a"

For more information, see the individual man pages for ifup(8), ifdown(8), ifreload(8).

Loopback Interface

Cumulus Linux has a preconfigured loopback interface. When the switch boots up, the loopback interface called lo is up and assigned an IP address of 127.0.0.1.

The loopback interface lo must always exist on the switch and must always be up.

To configure an IP address for the loopback interface:

cumulus@switch:~$ net add loopback lo ip address 10.10.10.1
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit
cumulus@switch:~$ nv set interface lo ip address 10.10.10.1
cumulus@switch:~$ nv config apply

Edit the /etc/network/interfaces file to add an address line:

auto lo
iface lo inet loopback
    address 10.10.10.1

  • If the IP address has no subnet mask, it automatically becomes a /32 IP address. For example, 10.10.10.1 is 10.10.10.1/32.
  • You can configure multiple IP addresses for the loopback interface.

Child Interfaces

By default, ifupdown2 recognizes and uses any interface present on the system that is a dependent (child) of an interface (for example, a VLAN, bond, or physical interface). You do not need to list interfaces in the /etc/network/interfaces file unless the interfaces need specific configuration for MTU, link speed, and so on. If you need to delete a child interface, delete all references to that interface from the /etc/network/interfaces file.

In the following example, swp1 and swp2 do not need an entry in the interfaces file. The following stanzas in /etc/network/interfaces provide the exact same configuration:

With Child Interfaces Defined

auto swp1
iface swp1

auto swp2
iface swp2

auto bridge
iface bridge
    bridge-vlan-aware yes
    bridge-ports swp1 swp2
    bridge-vids 1-100
    bridge-pvid 1
    bridge-stp on

Without Child Interfaces Defined

auto bridge
iface bridge
    bridge-vlan-aware yes
    bridge-ports swp1 swp2
    bridge-vids 1-100
    bridge-pvid 1
    bridge-stp on

In the following example, swp1.100 and swp2.100 do not need an entry in the interfaces file. The following stanzas defined in /etc/network/interfaces provide the exact same configuration:

With Child Interfaces Defined

auto swp1.100
iface swp1.100

auto swp2.100
iface swp2.100

auto br-100
iface br-100
    address 10.0.12.2/24
    address 2001:dad:beef::3/64
    bridge-ports swp1.100 swp2.100
    bridge-stp on

Without Child Interfaces Defined

auto br-100
iface br-100
    address 10.0.12.2/24
    address 2001:dad:beef::3/64
    bridge-ports swp1.100 swp2.100
    bridge-stp on

Interface Dependencies

ifupdown2 understands interface dependency relationships. When you run ifup and ifdown with all interfaces, the commands always run with all interfaces in dependency order. When you run ifup and ifdown with the interface list on the command line, the default behavior is to not run with dependents; however, if there are any built-in dependents, they do come up or go down.

To run with dependents when you specify the interface list, use the --with-depends option. The --with-depends option walks through all dependents in the dependency tree rooted at the interface you specify. Consider the following example configuration:

auto bond1
iface bond1
    address 100.0.0.2/16
    bond-slaves swp29 swp30

auto bond2
iface bond2
    address 100.0.0.5/16
    bond-slaves swp31 swp32

auto br2001
iface br2001
    address 12.0.1.3/24
    bridge-ports bond1.2001 bond2.2001
    bridge-stp on

The ifup --with-depends br2001 command brings up all dependents of br2001: bond1.2001, bond2.2001, bond1, bond2, bond1.2001, bond2.2001, swp29, swp30, swp31, swp32.

cumulus@switch:~$ sudo ifup --with-depends br2001

The ifdown --with-depends br2001 command brings down all dependents of br2001: bond1.2001, bond2.2001, bond1, bond2, bond1.2001, bond2.2001, swp29, swp30, swp31, swp32.

cumulus@switch:~$ sudo ifdown --with-depends br2001

ifdown2 always deletes logical interfaces after bringing them down. Use the --admin-state option if you only want to administratively bring the interface up or down. In the above example, ifdown br2001 deletes br2001.

To guide you through which interfaces go down and come up, use the --print-dependency option.

For example, run ifquery --print-dependency=list -a to show the dependency list for all interfaces:

cumulus@switch:~$ sudo ifquery --print-dependency=list -a
lo : None
eth0 : None
bond0 : ['swp25', 'swp26']
bond1 : ['swp29', 'swp30']
bond2 : ['swp31', 'swp32']
br0 : ['bond1', 'bond2']
bond1.2000 : ['bond1']
bond2.2000 : ['bond2']
br2000 : ['bond1.2000', 'bond2.2000']
bond1.2001 : ['bond1']
bond2.2001 : ['bond2']
br2001 : ['bond1.2001', 'bond2.2001']
swp40 : None
swp25 : None
swp26 : None
swp29 : None
swp30 : None
swp31 : None
swp32 : None

To print the dependency list of a single interface, run the ifquery --print-dependency=list <interface> command.

To show the dependency information for an interface in dot format, run the ifquery --print-dependency=dot <interface> command. The following example command shows the dependency information for interface br2001 in dot format:

cumulus@switch:~$ sudo ifquery --print-dependency=dot br2001
/* Generated by GvGen v.0.9 (http://software.inl.fr/trac/wiki/GvGen) */
digraph G {
    compound=true;
    node1 [label="br2001"];
    node2 [label="bond1.2001"];
    node3 [label="bond2.2001"];
    node4 [label="bond1"];
    node5 [label="bond2"];
    node6 [label="swp29"];
    node7 [label="swp30"];
    node8 [label="swp31"];
    node9 [label="swp32"];
    node1->node2;
    node1->node3;
    node2->node4;
    node3->node5;
    node4->node6;
    node4->node7;
    node5->node8;
    node5->node9;
}

You can use dot to render the graph on an external system.

To print the dependency information of the entire interfaces file, run the following command:

cumulus@switch:~$ sudo ifquery --print-dependency=dot -a >interfaces_all.dot

Subinterfaces

On Linux, an interface is a network device that can be either physical, (for example, swp1) or virtual (for example, vlan100). A VLAN subinterface is a VLAN device on an interface, and the VLAN ID appends to the parent interface using dot (.) VLAN notation. For example, a VLAN with ID 100 that is a subinterface of swp1 is swp1.100. The dot VLAN notation for a VLAN device name is a standard way to specify a VLAN device on Linux.

A VLAN subinterface only receives traffic tagged for that VLAN; therefore, swp1.100 only receives packets that have a VLAN 100 tag on switch port swp1. Any packets that transmit from swp1.100 have a VLAN 100 tag.

In an MLAG configuration, the peer link interface that connects the two switches in the MLAG pair has a VLAN subinterface named 4094. The peerlink.4094 subinterface only receives traffic tagged for VLAN 4094.

If you are using a VLAN subinterface, do not add that VLAN under the bridge stanza.

Parent Interfaces

When you run ifup on a logical interface (like a bridge, bond, or VLAN interface), if the ifup creates the logical interface, it also tries to execute on the upper (or parent) interfaces of the interface.

Consider this example configuration:

auto br100
iface br100
    bridge-ports bond1.100 bond2.100

auto bond1
iface bond1
    bond-slaves swp1 swp2

If you run ifdown bond1, ifdown deletes bond1 and the VLAN interface on bond1 (bond1.100); it also removes bond1 from the bridge br100. Next, when you run ifup bond1, it creates bond1 and the VLAN interface on bond1 (bond1.100); it also executes ifup br100 to add the bond VLAN interface (bond1.100) to the bridge br100.

There can be cases where an upper interface (like br100) is not in the right state, which can result in warnings. The warnings are harmless.

If you want to disable these warnings, set skip_upperifaces=1 in the /etc/network/ifupdown2/ifupdown2.conf file.

With skip_upperifaces=1, you have to execute ifup on the upper interfaces. In this case, you must run ifup br100 after an ifup bond1 to add bond1 back to bridge br100.

If you specify a subinterface, such as swp1.100, then run ifup swp1.100, Cumulus Linux creates the swp1 interface automatically in the kernel. Consider also specifying the parent interface swp1. A parent interface is one where any physical layer configuration can reside, such as link-speed 1000 or link-duplex full. If you create only swp1.100 and not swp1, you cannot run ifup swp1.

Interface IP Addresses

You can specify both IPv4 and IPv6 addresses for the same interface.

For IPv6 addresses, you can create or modify the IP address for an interface using either :: or 0:0:0 notation. For example,both 2620:149:43:c109:0:0:0:5 and 2001:DB8::1/126 are valid.

The following example commands configure three IP addresses for swp1; two IPv4 addresses and one IPv6 address.

cumulus@switch:~$ net add interface swp1 ip address 12.0.0.1/30
cumulus@switch:~$ net add interface swp1 ip address 12.0.0.2/30
cumulus@switch:~$ net add interface swp1 ipv6 address 2001:DB8::1/126
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

These commands create the following code snippet in the /etc/network/interfaces file:

auto swp1
iface swp1
    address 12.0.0.1/30
    address 12.0.0.2/30
    address 2001:DB8::1/126
  • NCLU adds the address method and address family when needed:

    auto lo
    iface lo inet loopback
    
cumulus@switch:~$ nv set interface swp1 ip address 10.0.0.1/30
cumulus@switch:~$ nv set interface swp1 ip address 10.0.0.2/30
cumulus@switch:~$ nv set interface swp1 ip address 2001:DB8::1/126
cumulus@switch:~$ nv config apply

In the /etc/network/interfaces file, list all IP addresses under the iface section.

auto swp1
iface swp1
    address 10.0.0.1/30
    address 10.0.0.2/30
    address 2001:DB8::1/126

The address method and address family are not mandatory; they default to inet/inet6 and static. However, you must specify inet/inet6 when you are creating DHCP or loopback interfaces.

auto lo
iface lo inet loopback

To make non-persistent changes to interfaces at runtime, use ip addr add:

cumulus@switch:~$ sudo ip addr add 10.0.0.1/30 dev swp1
cumulus@switch:~$ sudo ip addr add 2001:DB8::1/126 dev swp1

To remove an addresses from an interface, use ip addr del:

cumulus@switch:~$ sudo ip addr del 10.0.0.1/30 dev swp1
cumulus@switch:~$ sudo ip addr del 2001:DB8::1/126 dev swp1

Interface Descriptions

You can add a description (alias) to an interface.

Interface descriptions also appear in the SNMP OID IF-MIB::ifAlias

  • Interface descriptions can have a maximum of 256 characters.
  • Avoid using apostrophes or non-ASCII characters. Cumulus Linux does not parse these characters.

The following example commands create a description for swp1:

cumulus@switch:~$ net add interface swp1 alias hypervisor_port_1
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit
NVUE command is not supported.

In the /etc/network/interfaces file, add a description using the alias keyword:

cumulus@switch:~# sudo nano /etc/network/interfaces

auto swp1
iface swp1
    alias swp1 hypervisor_port_1

Interface Commands

You can specify user commands for an interface that run at pre-up, up, post-up, pre-down, down, and post-down.

You can add any valid command in the sequence to bring an interface up or down; however, limit the scope to network-related commands associated with the particular interface. For example, it does not make sense to install a Debian package on ifup of swp1, even though it is technically possible. See man interfaces for more details.

The following examples adds a command to an interface to enable proxy ARP:

cumulus@switch:~$ net add interface swp1 post-up echo 1 > /proc/sys/net/ipv4/conf/swp1/proxy_arp
cumulus@switch:~$ net add interface ip address 10.0.0.1/30
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

If your post-up command also starts, restarts, or reloads any systemd service, you must use the --no-block option with systemctl. Otherwise, that service or even the switch itself might hang after starting or restarting. For example, to restart the dhcrelay service after bringing up VLAN 100, first run:

cumulus@switch:~$ net add vlan 100 post-up systemctl --no-block restart dhcrelay.service

NVUE command is not supported.
cumulus@switch:~# sudo nano /etc/network/interfaces
auto swp1
iface swp1
    address 12.0.0.1/30
    post-up echo 1 > /proc/sys/net/ipv4/conf/swp1/proxy_arp

If your post-up command also starts, restarts, or reloads any systemd service, you must use the --no-block option with systemctl. Otherwise, that service or even the switch itself might hang after starting or restarting. For example, to restart the dhcrelay service after bringing up a VLAN, the /etc network/interfaces configuration looks like this:

auto bridge.100
iface bridge.100
    post-up systemctl --no-block restart dhcrelay.service

Source Interface File Snippets

Sourcing interface files helps organize and manage the /etc/network/interfaces file. For example:

cumulus@switch:~$ sudo cat /etc/network/interfaces
# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

source /etc/network/interfaces.d/bond0

The contents of the sourced file used above are:

cumulus@switch:~$ sudo cat /etc/network/interfaces.d/bond0
auto bond0
iface bond0
    address 14.0.0.9/30
    address 2001:ded:beef:2::1/64
    bond-slaves swp25 swp26

Port Ranges

To specify port ranges in commands:

Use commas to separate different port ranges (for example, swp1-46,10-12):

cumulus@switch:~$ net add bridge bridge ports swp1-4,6,10-12
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

These commands produce the following snippet in the /etc/network/interfaces file. The file renders the list of ports individually.

...
auto bridge
iface bridge
    bridge-ports swp1 swp2 swp3 swp4 swp6 swp10 swp11 swp12
    bridge-vlan-aware yes
auto swp1
iface swp1
...

Use commas to separate different port ranges (for example, swp1-46,10-12):

cumulus@switch:~$ nv set interface swp1-4,6,10-12 bridge domain br_default
cumulus@switch:~$ nv config apply

Use the glob keyword to specify bridge ports and bond slaves:

auto br0
iface br0
    bridge-ports glob swp1-6.100

auto br1
iface br1
    bridge-ports glob swp7-9.100  swp11.100 glob swp15-18.100

Mako Templates

ifupdown2 supports Mako-style templates. The Mako template engine processes the interfaces file before parsing.

Use the template to declare cookie-cutter bridges and to declare addresses in the interfaces file:

%for i in [1,12]:
auto swp${i}
iface swp${i}
    address 10.20.${i}.3/24

  • In Mako syntax, use square brackets ([1,12]) to specify a list of individual numbers. Use range(1,12) to specify a range of interfaces.
  • To test your template and confirm it evaluates correctly, run mako-render /etc/network/interfaces.

To comment out content in Mako templates, use double hash marks (##). For example:

## % for i in range(1, 4):
## auto swp${i}
## iface swp${i}
## % endfor
##

For more Mako template examples, refer to this knowledge base article.

ifupdown Scripts

Unlike the traditional ifupdown system, ifupdown2 does not run scripts installed in /etc/network/*/ automatically to configure network interfaces.

To enable or disable ifupdown2 scripting, edit the addon_scripts_support line in the /etc/network/ifupdown2/ifupdown2.conf file. 1 enables scripting and 2 disables scripting. For example:

cumulus@switch:~$ sudo nano /etc/network/ifupdown2/ifupdown2.conf
# Support executing of ifupdown style scripts.
# Note that by default python addon modules override scripts with the same name
addon_scripts_support=1

ifupdown2 sets the following environment variables when executing commands:

  • $IFACE represents the physical name of the interface; for example, br0 or vxlan42. The name comes from the /etc/network/interfaces file.
  • $LOGICAL represents the logical name (configuration name) of the interface.
  • $METHOD represents the address method; for example, loopback, DHCP, DHCP6, manual, static, and so on.
  • $ADDRFAM represents the address families associated with the interface in a comma-separated list; for example, "inet,inet6".

Troubleshooting

To see the link and administrative state of an interface:

cumulus@switch:~$ net show interface swp1
cumulus@switch:~$ nv show interface swp1 link state

In the following example, swp1 is administratively UP and the physical link is UP (LOWER_UP).

cumulus@switch:~$ ip link show dev swp1
3: swp1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 500
    link/ether 44:38:39:00:03:c1 brd ff:ff:ff:ff:ff:ff

To show the assigned IP address on an interface:

cumulus@switch:~$ net show interface swp1
cumulus@switch:~$ nv show interface swp1 ip address
cumulus@switch:~$ ip addr show swp1
3: swp1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 500
    link/ether 44:38:39:00:03:c1 brd ff:ff:ff:ff:ff:ff
    inet 192.0.2.1/30 scope global swp1
    inet 192.0.2.2/30 scope global swp1
    inet6 2001:DB8::1/126 scope global tentative
        valid_lft forever preferred_lft forever

To show the description (alias) for an interface:

cumulus@switch$ net show interface swp1
    Name   MAC                Speed     MTU   Mode
--  ----   -----------------  -------   -----  ---------
UP  swp1   44:38:39:00:00:04  1G        1500   Access/L2
Alias
-----
hypervisor_port_1

To show the interface description (alias) for all interfaces on the switch:

cumulus@switch:~$ net show interface alias
State    Name            Mode              Alias
-----    -------------   -------------     ------------------
UP       bond01          LACP
UP       bond02          LACP
UP       bridge          Bridge/L2
UP       eth0            Mgmt
UP       lo              Loopback          loopback interface
UP       mgmt            Interface/L3
UP       peerlink        LACP
UP       peerlink.4094   SubInt/L3
UP       swp1            BondMember        hypervisor_port_1
UP       swp2            BondMember        to Server02
...

To show the interface description for all interfaces on the switch in JSON format, run the net show interface alias json command.

cumulus@switch$ nv show interface swp1
cumulus@switch$ ip link show swp1
3: swp1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT qlen 500
    link/ether aa:aa:aa:aa:aa:bc brd ff:ff:ff:ff:ff:ff
    alias hypervisor_port_1

Considerations

Even though ifupdown2 supports the inclusion of multiple iface stanzas for the same interface, use a single iface stanza for each interface. If you must specify more than one iface stanza; for example, if the configuration for a single interface comes from many places, like a template or a sourced file, make sure the stanzas do not specify the same interface attributes. Otherwise, you see unexpected behavior.

In the following example, swp1 is in two file: /etc/network/interfaces and /etc/network/interfaces.d/speed_settings. ifupdown2 parses this configuration because the same attributes are not in multiple iface stanzas.

cumulus@switch:~$ sudo cat /etc/network/interfaces

source /etc/network/interfaces.d/speed_settings

auto swp1
iface swp1
  address 10.0.14.2/24

cumulus@switch:~$ cat /etc/network/interfaces.d/speed_settings

auto swp1
iface swp1
  link-speed 1000
  link-duplex full

ifupdown2 and sysctl

For sysctl commands in the pre-up, up, post-up, pre-down, down, and post-down lines that use the $IFACE variable, if the interface name contains a dot (.), ifupdown2 does not change the name to work with sysctl. For example, the interface name bridge.1 does not convert to bridge/1.

ifupdown2 and the gateway Parameter

The default route that the gateway parameter creates in ifupdown2 does not install in FRRouting, therefore does not redistribute into other routing protocols. Define a static default route instead, which installs in FRR and redistributes, if needed.

The following shows an example of the /etc/network/interfaces file when you use a static route instead of a gateway parameter:

auto swp2
iface swp2
address 172.16.3.3/24
up ip route add default via 172.16.3.2

Interface Name Limitations

Interface names can be a maximum of 15 characters. You cannot use a number for the first character and you cannot include a dash (-) in the name. In addition, you cannot use any name that matches with the regular expression .{0,13}\-v.*.

If you encounter issues, remove the interface name from the /etc/network/interfaces file, then restart the networking.service.

cumulus@switch:~$ sudo nano /etc/network/interfaces
cumulus@switch:~$ sudo systemctl restart networking.service

IP Address Scope

ifupdown2 does not honor the configured IP address scope setting in the /etc/network/interfaces file and treats all addresses as global. It does not report an error. Consider this example configuration:

auto swp2
iface swp2
    address 35.21.30.5/30
    address 3101:21:20::31/80
    scope link

When you run ifreload -a on this configuration, ifupdown2 considers all IP addresses as global.

cumulus@switch:~$ ip addr show swp2
5: swp2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 74:e6:e2:f5:62:82 brd ff:ff:ff:ff:ff:ff
inet 35.21.30.5/30 scope global swp2
valid_lft forever preferred_lft forever
inet6 3101:21:20::31/80 scope global
valid_lft forever preferred_lft forever
inet6 fe80::76e6:e2ff:fef5:6282/64 scope link
valid_lft forever preferred_lft forever

To work around this issue, configure the IP address scope:

cumulus@switch:~$ net add interface swp6 post-up ip address add 71.21.21.20/32 dev swp6 scope site
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit
NVUE command is not supported.

In the /etc/network/interfaces file, configure the IP address scope using post-up ip address add <address> dev <interface> scope <scope>. For example:

auto swp6
iface swp6
    post-up ip address add 71.21.21.20/32 dev swp6 scope site

Then run the ifreload -a command on this configuration.

The following configuration shows the correct scope:

cumulus@switch:~$ ip addr show swp6
9: swp6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 74:e6:e2:f5:62:86 brd ff:ff:ff:ff:ff:ff
inet 71.21.21.20/32 scope site swp6
valid_lft forever preferred_lft forever
inet6 fe80::76e6:e2ff:fef5:6286/64 scope link
valid_lft forever preferred_lft forever