Using OpenWrt as a wired AP including VLANs

Installing and Using OpenWrt Network and Wireless Configuration
9

Your bridge configuration for the guest and iot network is incorrect. It should look like the one of the lan network.

config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'fdea:673f:e258::/48'

config device
        option name 'eth1'
        option macaddr '######'
        option ipv6 '0'

config device
        option name 'eth0.1'
        option macaddr '####'
        option ipv6 '0'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0.1'
        
config device
        option name 'br-guest'
        option type 'bridge'
        list ports 'eth0.6'
        
config device
        option name 'br-iot'
        option type 'bridge'
        list ports 'eth0.7'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option ipaddr '192.168.3.51'
        option gateway '192.168.3.1'

config interface 'GuestNet'
        option proto 'dhcp'
        option device 'br-guest'

config interface 'IOTNet'
        option proto 'dhcp'
        option device 'br-iot'

config interface 'wan'
        option device 'eth1'
        option proto 'dhcp'

config interface 'wan6'
        option device 'eth1'
        option proto 'dhcpv6'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '1'
        option enable_vlan4k '1'

config switch_vlan
        option device 'switch0'
        option vlan '1'
        option ports '5t 0 1 2 3t'

config switch_vlan
        option device 'switch0'
        option vlan '6'
        option ports '5t 3t'

config switch_vlan
        option device 'switch0'
        option ports '5t 3t'
        option vlan '7'

If you run brctl show, you should see the wired and wireless interfaces as bridge members.

root@OpenWrt:~# brctl show
bridge name     bridge id               STP enabled     interfaces
br-lan          7fff.909a4a96c58a       no              wlan1
                                                        eth0.1
br-guest        7fff.909a4a96c58a       no              eth0.4
                                                        wlan1-1
br-test         7fff.909a4a96c58a       no              wlan1-2
                                                        eth0.3