Network configuration /etc/config/network

The default OpenWrt network stack of a typical home router looks like this:

LuCI → Network Comment Example
Firewall Rules for traffic between zones Forwarding Rules, Traffic Rules, Custom Rules
Firewall / Interfaces Network zone configuration WAN (Zone) LAN (Zone)
Interfaces → Interfaces IP configuration WAN WAN6 LAN
Interfaces → Devices Devices and bridge configuration eth0 br-lan (bridge config)
Switch / Wireless VLANs and wireless SSIDs VLAN 2 (eth0.2) VLAN 1 (eth0.1) OpenWrt OpenWrt
Switch / Wireless Internal jack labels and radio labels WAN (Interface) LAN 1 LAN 2 LAN 3 LAN 4 radio0 radio1
- Common vendor labels on backside of a device “Internet” “1” “2” “3” “4” “n/ac” “b/g/n”

Your device may vary slightly in features or numbering scheme. A minimal network configuration for a router usually consists of at least two interfaces (lan and wan) and their associated devices (br-lan and eth0), as well as a switch section if applicable.

Note that the labels WAN and LAN can mean different things depending on the context.

The central network configuration is handled by the UCI network subsystem, and stored in the file /etc/config/network. This UCI subsystem is responsible for defining switch VLANs, interface configurations and network routes. After network configuration customization you need to reload or restart the network service to apply the changes.

The network service manages both wired and wireless networking with netifid and wifi respectively.

Individual interfaces can be brought up with ifup name or down with ifdown name where name corresponds to the logical interface name of the corresponding config interface section. Keep in mind that ifup is normally enough to reload an interface since it includes ifdown.

Note that wireless interfaces are managed externally and ifup may break the relation to existing bridges. In such a case it is required to run wifi up after ifup in order to re-establish the bridge connection.

# Soft network reload
service network reload
# Hard network restart
service network restart
# Reconnect interface
ifdown wan6
ifup wan6
# Wireless reload
wifi down
wifi up
# List interfaces
ubus list network.interface.*
# Status information
ifstatus wan6

Here an example network UCI subsystem with default settings for a TL-WR1043ND:

config interface 'loopback'
	option device 'lo'
	option proto 'static'
	option ipaddr ''
	option netmask ''
config globals 'globals'
	option ula_prefix 'fd27:70fa:5c1d::/48'
config device 'lan_br'
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth0.1'
config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask ''
	option ip6assign '60'
	option ipaddr ''
config interface 'wan'
	option device 'eth0.2'
	option proto 'dhcp'
config interface 'wan6'
	option device 'eth0.2'
	option proto 'dhcpv6'
config switch
	option name 'switch0'
	option reset '1'
	option enable_vlan '1'
config switch_vlan
	option device 'switch0'
	option vlan '1'
	option ports '1 2 3 4 5t'
config switch_vlan
	option device 'switch0'
	option vlan '2'
	option ports '0 5t'

The globals section contains interface-independent options affecting the network configuration in general.

config globals 'globals'
	option ula_prefix 'fd27:70fa:5c1d::/48'
Name Type Required Default Description
ula_prefix IPv6-prefix or auto no (none) IPv6 ULA prefix for this device: auto - auto-generate a new ULA prefix
packet_steering boolean no (none) Use every CPU to handle packet traffic

The device section is optional when L2 and L3 is the same device, i.e. MAC and IP on the same physical interface.

config device 'lan_br'
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth0.1'
Name Type Required Default Description
name string yes (none) L3 device name.
Needs to match the device option of the respective interface section
macaddr string no (none) MAC address overriding the default one for this device, e.g. 62:11:22:aa:bb:cc
type string no (none) If set to bridge, creates a bridge of the given name using L2 devices listed in ports and wireless interfaces assigned using the network option in the wireless configuration
ifname string no(*) (none) The base L2 device required when using the macvlan device type. Install the kmod-macvlan package if necessary.
ports list no (none) List of L2 device names.

TODO: move everything related to bridges and layer 2 here.

Sections of the type interface declare logical networks serving as containers for IP address settings, aliases, routes, physical interface names and firewall rules - they play a central role within the OpenWrt configuration concept.

A minimal interface declaration consists of the following lines:

config 'interface' 'wan'
	option 'proto' 'dhcp'
	option 'device' 'eth0.2'
  • wan is a unique logical interface name
  • dhcp specifies the interface protocol, DHCP in this example
  • eth0.2 is the physical interface associated with this section

The Linux kernel limits the physical interface name length to max 14 usable characters including the automatically added prefix that is added for some protocols (e.g.6in4, pppoa-, pppoe-, gre4t-) or with bridges (br-).

Depending on the protocol type, the logical interface name may thus be limited to only 8 characters. E.g. abcde6789 is a valid interface name for a normal interface using dhcp, but not for a pppoe interface where the final name would be pppoe-abcde6789, which is more than 14 chars.

If using .VLAN notation, an additional 5 characters may be needed, limiting the “parent” interface name to 3 characters for protocols such as GRE. abcd.NNNNgre4t-abc.NNNN for 14 characters.

Using a too long name will lead to silent errors, with interface creation or modification not being successful. Example of this silent error when using br- and different length .VLAN notation can be seen in the forum at

The interface protocol may be one of the following:

Protocol Description Program
static Static configuration with fixed address and netmask ip/ifconfig
dhcp Address and netmask are assigned by DHCP udhcpc (Busybox)
dhcpv6 Address and netmask are assigned by DHCPv6 odhcpc6c
ppp PPP protocol - dialup modem connections pppd
pppoe PPP over Ethernet - DSL broadband connection pppd + plugin
pppoa PPP over ATM - DSL connection using a builtin modem pppd + plugin ...
3g CDMA, UMTS or GPRS connection using an AT-style 3G modem comgt
qmi USB modems using QMI protocol uqmi
ncm USB modems using NCM protocol comgt-ncm + ?
wwan USB modems with protocol autodetection wwan
hnet Self-managing home network (HNCP) hnet-full
pptp Connection via PPtP VPN ?
6in4 IPv6-in-IPv4 tunnel for use with Tunnel Brokers like ?
aiccu Anything-in-anything tunnel aiccu
6to4 Stateless IPv6 over IPv4 transport ?
6rd IPv6 rapid deployment 6rd
dslite Dual-Stack Lite ds-lite
l2tp PPP over L2TP Pseudowire Tunnel xl2tpd
relay relayd pseudo-bridge relayd
gre, gretap GRE over IPv4 gre + kmod-gre
grev6, grev6tap GRE over IPv6 gre + kmod-gre6
vti VTI over IPv4 vti + kmod-ip_vti
vtiv6 VTI over IPv6 vti + kmod-ip6_vti
vxlan VXLAN protocol for layer 2 virtualization, see here for further information and a configuration example vxlan + kmod-vxlan + ip-full
none Unspecified protocol, therefore all the other interface settings will be ignored (like disabling the configuration) -

Depending on the used interface protocol several other options may be required for a complete interface declaration. The corresponding options for each protocol are listed below. Options marked as “yes” in the “Required” column must be defined in the interface section if the corresponding protocol is used, options marked as “no” may be defined but can be omitted as well.

:!: If an interface section has no protocol defined (not even none ), the other settings are completely ignored. The result is that, if the interface section is mentioning a physical network interface (i.e. eth0), this will be down even if a cable is connected (with proto 'none' the interface is up).

Common options options valid for all protocol types.

Name Type Required Default Description
device string yes(*) (none) L3 device name, such as eth0.1, eth2, tun0, br-lan, etc.
Needs to match the name option of the respective device section.
:!: Do not specify wireless interfaces as their names and behavior can be dynamic and unpredictable, instead assign wireless interfaces to bridges using the network option in wireless configuration.
This option may be empty or missing if only a wireless interface references this network or if the protocol is pptp, pppoa, 6in4, etc.
mtu number no (none) Override the default MTU on this interface
auto boolean no 0 for proto none, else 1 Specifies whether to bring up interface on boot
ipv6 boolean no 1 Specifies whether to enable (1) or disable (0) IPv6 on this interface (Barrier Breaker and later only)
force_link boolean no 1 for protocol static, else 0 Specifies whether ip address, route, and optionally gateway are assigned to the interface regardless of the link being active ('1') or only after the link has become active ('0'); when set to '1', carrier sense events do not invoke hotplug handlers
disabled boolean no 0 enable or disable the interface section
ip4table string no (none) IPv4 routing table for routes of this interface, see: ip rule show; ip route show table <ip4table>
ip6table string no (none) IPv6 routing table for routes of this interface, see: ip -6 rule show; ip -6 route show table <ip6table>

:!: All bridge settings are optional.

Name Type Default Range Description
bridge_empty boolean 0 0, 1 Enables creating empty bridges
vlan_filtering boolean 0 0, 1 Enables VLAN aware bridge mode
igmp_snooping boolean 0 0, 1 Enables IGMP snooping on the bridge, an optimization that only sends multicast traffic to ports with multicast clients or routers
multicast_querier boolean (igmp_snooping setting) 0, 1 IGMP Enables the bridge as a multicast querier, which keeps the multicast group to port mappings current. Only one querier is elected per subnet
query_interval number 12500 - IGMP Interval in 1/100 seconds between querier general queries (so default is 125 seconds)
query_response_interval number 1000 (less than query_interval) IGMP Max time in 1/100 seconds responses to queries should be sent (increase to make IGMP less bursty)
last_member_interval number 100 - IGMP Max time in 1/100s responses to queries after “leave group” messages (the leave latency)
hash_max number 512 - IGMP Size of kernel multicast hash table (larger to avoid collisions that disable snooping)
robustness number 2 - IGMP Sets Startup Query Count and Last Member Count. Also combined with query_interval and query_response_interval to calculate Group Membership Interval and “other querier” timeout (both other values must be set)
stp boolean 0 0, 1 Enables the Spanning Tree Protocol (STP) which prevents network loops (and resulting packet storms)
forward_delay number 2:!: 2 - 30 STP Delay in seconds between port state transitions from Listening → Learning → Forwarding (i.e. bridge ports will be blocked for 2x this value when brought up) :!: NOTE The default 2 is below the minimum 802.1D standard of 4, and STP will be ignored by conforming switches. Set to at least 4 to work with non-OpenWrt switches!
hello_time number 2 1 - 10 STP Seconds between STP packets
priority number 32767 0 - 65535 STP Bridge Priority. Lowest priority bridge becomes the Root of the Spanning Tree; most switches default to 32768
ageing_time number 300 10 - 1000000 STP Expire in seconds for dynamic MAC entries in the Filtering DB
max_age number 20 6 - 40 STP After current Root Bridge absent this many seconds, attempt to become the Root Bridge (effects the speed a dead bridge is identified)

This only applies to OpenWrt 21.02 and later, and only for targets that have switched to a DSA driver.

FIXME, see: DSA networking

As of OpenWrt 21.02, swconfig is being phased out and is being replaced with DSA.

This guide applies to all versions of OpenWrt before 21.02. It also applies to non-DSA targets in OpenWrt 21.02.

For many users, the default switch configuration is sufficient. Should the user need to configure the switch differently, LuCI, UCI, or direct editing of /etc/config/network may be used to achieve different configurations. Prior to any reconfiguration of the switch, an understanding of the default configuration is important. As an example, some devices have a single switch-connected interface, and other have two or more.

See also:

The identifier for the switch(es) may be obtained using:

# swconfig list
Found: switch0 - ag71xx-mdio.0

With the identifier known, the configuration can be viewed:

# swconfig dev switch0 show
Global attributes:
	enable_vlan: 1
	enable_mirror_rx: 0
	enable_mirror_tx: 0
	mirror_monitor_port: 0
	mirror_source_port: 0
	arl_age_time: 300
	arl_table: address resolution table

There are three types of switch-related configuration stanzas, switch, switch_vlan, and switch_port.

Not all options are available on all hardware. Some limitations may be found with swconfig dev <dev> help. After making changes, check the output of swconfig to determine if the configuration was accepted by the switch hardware.

FIXME: The list of options may be incomplete. The details of each option need additional discovery and documentation, including checking of the underlying code. The source of restrictions on value ranges has yet to be identified. Valid values should be confirmed in the code.

Option Name Type Required Default Impact Notes
name string yes (none) defines which switch to configure
reset boolean 1
enable_vlan boolean 1 Default may differ by hardware
enable_mirror_rx boolean no 0 Mirror received packets from the mirror_source_port to the mirror_monitor_port
enable_mirror_tx boolean no 0 Mirror transmitted packets from the mirror_source_port to the mirror_monitor_port
mirror_monitor_port integer no 0 Switch port to which packets are mirrored
mirror_source_port integer no 0 Switch port from which packets are mirrored
arl_age_time integer no 300 Adjust the address-resolution (MAC) table's aging time (seconds) Default may differ by hardware
igmp_snooping boolean no 0 Enable IGMP snooping Unconfirmed if can be set. Unknown how it interacts with interface- or port-level IGMP snooping.
igmp_v3 boolean no 0 Unconfirmed if can be set. Unknown how it interacts with interface- or port-level IGMP snooping.
Option Name Type Required Default Impact Notes
description string no (none) A human-readable description of the VLAN configuration
device string yes (none) defines which switch to configure
vlan integer yes (none) The vlan “table index” to configure May be limited to 127 or another number. See the output of swconfig dev <dev> help for limit. Sets defaults for VLAN tag and PVID.
vid integer no vlan The VLAN tag number to use See the output of swconfig dev <dev> help for limit. VLANs 0 and 4095 are often considered “special use”.
ports string yes (none) A string of space-separated port indicies that should be associated with the VLAN. Adding the suffix t to a port indicates that egress packets should be tagged, for example '0 1 3t 5t' The suffixes * and u are referred to in docs:guide-user:network:switch with reference to certain Broadcom switches in the context of older releases.
Option Name Type Required Default Impact Notes
device string yes (none) defines which switch to configure
port integer yes (none) The port index to configure
pvid integer no Port PVID; the VLAN tag†† to assign to untagged ingress packets †Typically defaults one of the VLAN tags associated with the port. Logic not clear when there are multiple VLANs on the port. '0' can occur. Certain values have been rejected; logic not clear on limitations. ††May refer to the VLAN “index” rather than the VLAN tag itself (unconfirmed).
enable_eee boolean no 0 Enable “energy saving” features
igmp_snooping boolean no 0 Enable IGMP snooping Unconfirmed if can be set. Unknown how it interacts with interface- or switch-level IGMP snooping.
igmp_v3 boolean no 0 Unconfirmed if can be set. Unknown how it interacts with interface- or switch-level IGMP snooping.
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  • Last modified: 2024/05/29 20:24
  • by zorun