Wifi extender over ethernet constant DHCP spam (DHCPDISCOVER)

tojestzart · June 11, 2025, 7:21am

Hi i have two routers main (Asus RT-AX53U) OpenWrt SNAPSHOT (r29528-ffde9a9fe9) and second as extender (Cudy TR1200) OpenWrt 24.10.1 (r28597-0425664679)
I used chatgpt to help set all settings trought LUCI and it was almost exactly same as in this guide --> https://openwrt.org/docs/guide-user/network/wifi/wifiextenders/bridgedap beyond this i added manually WAN to LAN

comparing to this guide above all settings are same,


root@OpenWrt:~# cat /etc/config/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 'fde2:1be8:8d58::/48'
        option packet_steering '1'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0.1'
        list ports 'eth0.2'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option ipaddr '192.168.1.2'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option gateway '192.168.1.1'
        option dns '192.168.1.1'
        option ipv6 'off'

config interface 'wan'
        option device 'eth0.2'
        option proto 'dhcp'
        option ipv6 'off'

config interface 'wan6'
        option device 'eth0.2'
        option proto 'dhcpv6'
        option disabled '1'
        option auto '0'
        option reqaddress 'try'
        option reqprefix 'auto'
        option norelease '1'

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

config switch_vlan
        option device 'switch0'
        option vlan '1'
        option ports '0 6t'

config switch_vlan
        option device 'switch0'
        option vlan '2'
        option ports '1 6t'

root@OpenWrt:~#

root@OpenWrt:~# cat /etc/config/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 'fde2:1be8:8d58::/48'
        option packet_steering '1'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0.1'
        list ports 'eth0.2'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option ipaddr '192.168.1.2'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option gateway '192.168.1.1'
        option dns '192.168.1.1'
        option ipv6 'off'

config interface 'wan'
        option device 'eth0.2'
        option proto 'dhcp'
        option ipv6 'off'

config interface 'wan6'
        option device 'eth0.2'
        option proto 'dhcpv6'
        option disabled '1'
        option auto '0'
        option reqaddress 'try'
        option reqprefix 'auto'
        option norelease '1'

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

config switch_vlan
        option device 'switch0'
        option vlan '1'
        option ports '0 6t'

config switch_vlan
        option device 'switch0'
        option vlan '2'
        option ports '1 6t'

root@OpenWrt:~#
root@OpenWrt:~# cat /etc/config/wireless

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'platform/10300000.wmac'
        option band '2g'
        option channel '1'
        option htmode 'HT20'
        option disabled '1'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'

config wifi-device 'radio1'
        option type 'mac80211'
        option path 'pci0000:00/0000:00:00.0/0000:01:00.0'
        option band '5g'
        option channel '36'
        option htmode 'VHT80'
        option cell_density '0'
        option country 'PL'
        option txpower '7'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option ssid 'JAN_5G'
        option encryption 'psk2'
        option key 'PASSWORD'

root@OpenWrt:~#

root@OpenWrt:~# cat /etc/config/dhcp

config dnsmasq
        option domainneeded '1'
        option boguspriv '1'
        option filterwin2k '0'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option local '/lan/'
        option domain 'lan'
        option expandhosts '1'
        option nonegcache '0'
        option cachesize '1000'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
        option nonwildcard '1'
        option localservice '1'
        option ednspacket_max '1232'
        option filter_aaaa '0'
        option filter_a '0'

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option ignore '1'
        option dhcpv6 'disabled'

config dhcp 'wan'
        option interface 'wan'
        option ignore '1'

config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
        option loglevel '4'

root@OpenWrt:~#

Log from main router (Asus RT-AX53U) offers constantly DHCP for some reason

Wed Jun 11 01:47:26 2025 daemon.info dnsmasq-dhcp[1]: DHCPDISCOVER(br-lan) 80:af:ca:57:XX:XX
Wed Jun 11 01:47:26 2025 daemon.info dnsmasq-dhcp[1]: DHCPOFFER(br-lan) 192.168.1.134 80:af:ca:57:XX:XX
Wed Jun 11 01:47:29 2025 daemon.info dnsmasq-dhcp[1]: DHCPDISCOVER(br-lan) 80:af:ca:57:XX:XX
Wed Jun 11 01:47:29 2025 daemon.info dnsmasq-dhcp[1]: DHCPOFFER(br-lan) 192.168.1.134 80:af:ca:57:XX:XX
Wed Jun 11 01:47:32 2025 daemon.info dnsmasq-dhcp[1]: DHCPDISCOVER(br-lan) 80:af:ca:57:XX:XX
Wed Jun 11 01:47:32 2025 daemon.info dnsmasq-dhcp[1]: DHCPOFFER(br-lan) 192.168.1.134 80:af:ca:57:XX:XX
Wed Jun 11 01:47:35 2025 daemon.info dnsmasq-dhcp[1]: DHCPDISCOVER(br-lan) 80:af:ca:57:XX:XX
Wed Jun 11 01:47:35 2025 daemon.info dnsmasq-dhcp[1]: DHCPOFFER(br-lan) 192.168.1.134 80:af:ca:57:XX:XX
Wed Jun 11 01:47:38 2025 daemon.info dnsmasq-dhcp[1]: DHCPDISCOVER(br-lan) 80:af:ca:57:XX:XX
Wed Jun 11 01:47:38 2025 daemon.info dnsmasq-dhcp[1]: DHCPOFFER(br-lan) 192.168.1.134 80:af:ca:57:XX:XX
Wed Jun 11 01:47:41 2025 daemon.info dnsmasq-dhcp[1]: DHCPDISCOVER(br-lan) 80:af:ca:57:XX:XX
Wed Jun 11 01:47:41 2025 daemon.info dnsmasq-dhcp[1]: DHCPOFFER(br-lan) 192.168.1.134 80:af:ca:57:XX:XX

Target: Cudy TR1200 need to have static IP, DHCP assigning has to be on main router
Question is why its spamming if i did everything correct?

lleachii · June 11, 2025, 7:25am

Why?

You didn't - you combined WAN and LAN. It's not correct to have eth0.2 configured as both WAN and LAN.

brada4 · June 11, 2025, 8:18am

Your chatbot gave you swconfig style config for a dsa device, reset and start fresh. Youll need br-lan.123 style vlans then tag/untag that on physical ports (not DSA master ports)