Guest WiFi: no DHCP

Installing and Using OpenWrt Network and Wireless Configuration
1

Hi!

I'm trying to configure a guest WiFi on my OpenWrt Router (v24.10.1), but can't get my devices assigned any IP using DHCP.
I followed the cli guide and also the LuCi guide, but couldn't get it to work.

Here's is my current config:

{
	"kernel": "6.6.86",
	"hostname": "openwrt-wiebkebuero",
	"system": "ARMv8 Processor rev 4",
	"model": "ASUS RT-AX59U",
	"board_name": "asus,rt-ax59u",
	"rootfs_type": "squashfs",
	"release": {
		"distribution": "OpenWrt",
		"version": "24.10.1",
		"revision": "r28597-0425664679",
		"target": "mediatek/filogic",
		"description": "OpenWrt 24.10.1 r28597-0425664679",
		"builddate": "1744562312"
	}
}

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 'fdfa:99c2:a797::/48'
	option packet_steering '1'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'lan1'
	list ports 'lan2'
	list ports 'lan3'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ip6assign '60'
	list ipaddr '192.168.1.1/24'

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

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

config device 'guest_dev'
	option type 'bridge'
	option name 'br-guest'

config interface 'guest'
	option proto 'static'
	option device 'br-guest'
	list ipaddr '192.168.3.1/24'

/etc/config/wireless

config wifi-device 'radio0'
	option type 'mac80211'
	option path 'platform/soc/18000000.wifi'
	option band '2g'
	option channel 'auto'
	option htmode 'HE20'
	option cell_density '0'
	option country 'DE'

config wifi-device 'radio1'
	option type 'mac80211'
	option path 'platform/soc/18000000.wifi+1'
	option band '5g'
	option channel 'auto'
	option htmode 'HE80'
	option cell_density '0'

config wifi-iface 'wifinet2'
	option device 'radio0'
	option mode 'ap'
	option ssid 'wlan99'
	option encryption 'sae-mixed'
	option key 'xxxxxxxxx'
	option network 'lan'
	option ocv '0'
	option wpa_disable_eapol_key_retries '1'

config wifi-iface 'wifinet1'
	option device 'radio1'
	option mode 'ap'
	option ssid 'wlan99_5GHz'
	option encryption 'sae-mixed'
	option key 'xxxxxxxxx'
	option network 'lan'
	option ocv '0'
	option wpa_disable_eapol_key_retries '1'

config wifi-iface 'wifinet3'
	option device 'radio0'
	option mode 'ap'
	option ssid 'wlan5'
	option encryption 'sae-mixed'
	option key 'xxxxxxxxx'
	option network 'lan'
	option ocv '0'
	option wpa_disable_eapol_key_retries '1'

config wifi-iface 'guest'
	option device 'radio0'
	option mode 'ap'
	option network 'guest'
	option ssid 'guest'
	option encryption 'sae-mixed'
	option key 'xxxxxxxxx'
	option ocv '0'
	option wpa_disable_eapol_key_retries '1'

/etc/config/dhcp

config dnsmasq
	option domainneeded '1'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option local '/lan/'
	option domain 'lan'
	option expandhosts '1'
	option cachesize '1000'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
	option localservice '1'
	option ednspacket_max '1232'
	option authoritative '1'
	list interface 'lan'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '6h'
	option dhcpv4 'server'
	option dhcpv6 'relay'
	option ra 'hybrid'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'

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'

config dhcp 'guest'
	option interface 'guest'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option force '1'

/etc/config/firewall

config defaults
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'
	option synflood_protect '1'

config zone
	option name 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	list network 'lan'

config zone
	option name 'wan'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'
	option masq '1'
	option mtu_fix '1'
	list network 'wan'
	list network 'wan6'

config forwarding
	option src 'lan'
	option dest 'wan'

config rule
	option name 'Allow-DHCP-Renew'
	option src 'wan'
	option proto 'udp'
	option dest_port '68'
	option target 'ACCEPT'
	option family 'ipv4'

config rule
	option name 'Allow-Ping'
	option src 'wan'
	option proto 'icmp'
	option icmp_type 'echo-request'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-IGMP'
	option src 'wan'
	option proto 'igmp'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-DHCPv6'
	option src 'wan'
	option proto 'udp'
	option dest_port '546'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-MLD'
	option src 'wan'
	option proto 'icmp'
	option src_ip 'fe80::/10'
	list icmp_type '130/0'
	list icmp_type '131/0'
	list icmp_type '132/0'
	list icmp_type '143/0'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Input'
	option src 'wan'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	list icmp_type 'router-solicitation'
	list icmp_type 'neighbour-solicitation'
	list icmp_type 'router-advertisement'
	list icmp_type 'neighbour-advertisement'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Forward'
	option src 'wan'
	option dest '*'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-IPSec-ESP'
	option src 'wan'
	option dest 'lan'
	option proto 'esp'
	option target 'ACCEPT'
	option enabled '0'

config rule
	option name 'Allow-ISAKMP'
	option src 'wan'
	option dest 'lan'
	option dest_port '500'
	option proto 'udp'
	option target 'ACCEPT'

config zone 'guest'
	option name 'guest'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'
	list network 'guest'

config rule 'guest_dns'
	option name 'Allow-DNS-Guest'
	option src 'guest'
	option dest_port '53'
	option proto 'tcp udp'
	option target 'ACCEPT'

config rule 'guest_dhcp'
	option name 'Allow-DHCP-Guest'
	option src 'guest'
	option dest_port '67-68'
	option proto 'udp'
	option family 'ipv4'
	option target 'ACCEPT'

config forwarding
	option src 'guest'
	option dest 'wan'

If I assign a static IP from the 192.168.3.0 subnet it works as expected. So it seems the DHCP messages are blocked!?

BTW: The cli guide only creates a firewall rule for DHCP port 67, but not 68!?

Thx in advance!

2

Try this, remove list interface 'lan'

P.S using sae-mixed for Wireless encryption might not work with all clients

2 Likes
3

those two differ, the 2nd one is for an AP ?

there's also https://openwrt.org/docs/guide-user/network/wifi/guestwifi/configuration_webinterface

4

Removing list interface 'lan' did the trick @egc

Thank you very much!!

1 Like
5

I had the same problem, with my devices unable to connect to my guest WiFi, and I found the problem was that I had created a single rule for DNS and DHCP, with Protocol TCP and UDP and Destination Ports 53 67 68.

After I split it into two rules, one for DNS on TCP and UDP port 53, and one for DHCP on UDP port 67, it worked, but I'm curious why it doesn't work when they're combined into a single rule, as the Allow Admin rule has several destination ports?

6

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