Dump AP guest network issues

routerboy · November 27, 2022, 8:36pm

Hi, Trying to set up a 'dumb' AP with a couple APs.
The setup is based on these links:

gist.github.com

https://gist.github.com/wirecuttr/32d9159a82f779e4a175b528522ba8f4

dumb-ap-wired-link.sh

# ========================================================
# Setup a Dumb AP, Wired backbone for OpenWRT / LEDE
# ========================================================
# Set lan logical interface as bridge (to allow bridge multiple physical interfaces)
uci set network.lan.type='bridge'
# assign WAN physical interface to LAN (will be available as an additional LAN port now)
uci set network.lan.ifname="$(uci get network.lan.ifname) $(uci get network.wan.ifname)"
uci del network.wan.ifname
# Remove wan logical interface, since we will not need it.
uci del network.wan

This file has been truncated. show original

Set up is:
Two Archer C7 v2s
Main router is 192.168.30.1
AP is 192.168.10.1
On the AP I'm trying to set up two SSIDs. One to extend my main WIFI and the other for guest WiFi. Guest Wifi should have internet access only. I'm not using VLANs as I've read the Archer C7 doesn't have good VLAN support.

Main router is working fine, so I'll focus on the AP. AP is wired to the main router LAN port to LAN port. The WAN port on the AP is not used.
On the AP, wired into a LAN connection or connected to the main/default WiFi connection work fine. I can access the internet and the 192.168.30.x LAN.
When I connect to the guest WiFi, clients connect and get a 192.168.10.x address. gateway 192.168.10.1, but can't reach anything. i.e., I tried pinging 8.8.8.8, 192.168.30.1, 192.168.10.1 and all are unreachable.
The guest WiFi clients seem to be getting 192.168.10.1 as a dns server, even though I've specified a custom dns server (I have pihole running on 192.168.30.250)

Any help much appreciated!
config is below:

/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 'fd3d:6fb4:b81c::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth1.1'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.30.248'
	option gateway '192.168.30.1'

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 '2 3 4 5 0t'

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

config interface 'guest'
	option type 'bridge'
	option proto 'static'
	option ipaddr '192.168.10.1'
	option netmask '255.255.255.0'
	option dns '192.168.30.250 208.67.220.123 208.67.222.123'

/etc/config/firewall

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

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

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

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'

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 network 'guest'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'

config forwarding 'guest_lan'
	option src 'guest'
	option dest 'lan'

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

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

config rule 'guest_fwd'
	option name 'Block-guest'
	option src 'guest'
	option dest_ip '192.168.30.0/24'
	option proto 'all'
	option target 'DROP'

/etc/config/wireless


config wifi-device 'radio0'
	option type 'mac80211'
	option path 'pci0000:00/0000:00:00.0'
	option channel '36'
	option band '5g'
	option htmode 'VHT80'
	option disabled '0'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option ssid 'OpenWrt'
	option encryption 'sae-mixed'
	option key 'XXXXXXXX'

config wifi-device 'radio1'
	option type 'mac80211'
	option path 'platform/ahb/18100000.wmac'
	option channel '1'
	option band '2g'
	option htmode 'HT20'
	option disabled '0'

config wifi-iface 'default_radio1'
	option device 'radio1'
	option network 'lan'
	option mode 'ap'
	option ssid 'OpenWrt'
	option encryption 'sae-mixed'
	option key 'XXXXXXXX'

config wifi-iface 'guest'
	option device 'radio1'
	option mode 'ap'
	option network 'guest'
	option ssid 'guest'
	option encryption 'sae-mixed'
	option key 'XXXXXXXX'
	option isolate '1'

/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 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'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	option ra_slaac '1'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	option ignore '1'

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 dhcpv4 'server'

Pico · November 27, 2022, 8:45pm

could it be you missed the „ Also enable masquarading for lan“ checkmark?

psherman · November 27, 2022, 8:46pm

you need to enable masquerading on the lan zone.

config zone 'lan'
	option name 'lan'
	list network 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	option masq '1'

The bridge needs to be defined outside the guest network interface stanza.... make it look like this instead:

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

config interface 'guest'
	option device 'br-guest'
	option proto 'static'
	option ipaddr '192.168.10.1'
	option netmask '255.255.255.0'
	option dns '192.168.30.250 208.67.220.123 208.67.222.123'

The DNS in the guest zone won't work the way you expect...
first, the 192.168.30.250 address is unreachable because you block all 192.168.30.0/24 addresses in your firewall. Second, DNS entries here are not what will be used for the guest hosts. Instead, you can either advertise those via your DHCP server option 6, or you can set the DNS for the lan (which is the uplink interface) and/or set the resolvers in the dnsmasq settings. This won't force the devices to use those defined DNS servers, so individual devices/users can override, but that is another story.

trendy · November 28, 2022, 11:36am

You should follow this guide starting from a default OpenWrt installation. The other guides are based on the fact that OpenWrt is routing and not a dumbAP.

routerboy · November 28, 2022, 8:41pm

Thanks. I did look at that. It's a sub page under the main Guest Wi-Fi page I linked to in my post.

routerboy · November 28, 2022, 9:26pm

Thanks @psherman.
I've updated the network and firewall files are you indicated. I'm a bit unclear on the dns part. I've removed option dns from the network file and to the dhcp file added:
dhcp.guest.dhcp_options='192.168.30.250,208.67.220.123.208.67.222.123'

At this point I can ping 8.8.8.8. I can also 192.168.30.x addresss, but I was wanting to block main network access from the guest network which doesn't seem to be the case.
I cannot ping microsoft.com successfully so the DNS is still not right I suppose.

Updated configs are below

/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 'fd3d:6fb4:b81c::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth1.1'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.30.248'
	option gateway '192.168.30.1'

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 '2 3 4 5 0t'

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

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

config interface 'guest'
	option device 'br-guest'
	option proto 'static'
	option ipaddr '192.168.10.1'
	option netmask '255.255.255.0'
	option gateway '192.168.30.1'

/etc/config/firewall


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

config zone 'lan'
	option name 'lan'
	list network 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	option masq '1'

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

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'

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 network 'guest'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'

config forwarding 'guest_lan'
	option src 'guest'
	option dest 'lan'

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

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

config rule 'guest_fwd'
	option name 'Block-guest'
	option src 'guest'
	option dest_ip '192.168.30.0/24'
	option proto 'all'
	option target 'DROP'

/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 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'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	option ra_slaac '1'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	option ignore '1'

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 dhcpv4 'server'
	option dhcp_options '6,192.168.30.250,208.67.220.123 208.67.222.123'

What's next?

psherman · November 28, 2022, 9:32pm

Remove 192.168.30.250 since your guest hosts cannot reach any of the hosts on that network (firewall rules). Restart the router and test again.

There are a few ways you can make that local dns server work, but let’s make sure everything else is okay first.

routerboy · November 28, 2022, 9:59pm

OK. Changed: dhcp.guest.dhcp_options='6,8.8.8.8' for now and rebooted

SSH'd into the dumb AP:
The 192.168.30.x network is reachable.
I can ping 192.168.30.250.
I can ping 8.8.8.8
I cannot ping microsoft.com

If join the guest WiFI, same results from the client. I can also open the pihole admin in a browser at http://192.168.30.250.

For completeness here is another dump of the configs

/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 'fd3d:6fb4:b81c::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth1.1'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.30.248'
	option gateway '192.168.30.1'

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 '2 3 4 5 0t'

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

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

config interface 'guest'
	option proto 'static'
	option device 'br-guest'
	option ipaddr '192.168.10.1'
	option netmask '255.255.255.0'

/etc/config/firewall

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

config zone 'lan'
	option name 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	option masq '1'
	list network 'lan'

config zone 'wan'
	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'

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 forwarding 'guest_lan'
	option src 'guest'
	option dest 'lan'

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

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

config rule 'guest_fwd'
	option name 'Block-guest'
	option src 'guest'
	option dest_ip '192.168.30.0/24'
	option proto 'all'
	option target 'DROP'

/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 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'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	option ra_slaac '1'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	option ignore '1'

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 dhcpv4 'server'
	option dhcp_options '6,8.8.8.8'

psherman · November 28, 2022, 10:05pm

From the dumb ap, an ssh session that reveals dns is not working points to the system not having a dns setup on the upstream interface.

routerboy:

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.30.248'
	option gateway '192.168.30.1'

The above needs dns defined if you want to resolve from the router itself.

What dns shows up on the host that is connected to the guest network?

routerboy · November 29, 2022, 12:07am

On the guest network client, the dns is showing as 192.168.10.1.

Ok I added upstream dns server on the lan interface and also removed dhcp_options 6

Now from an SSH session and also on the client I have internet access and DNS is resolving OK.
The one problem is that the guest WiFi network has full access to the 192.168.30.x network.
From SSH and a client I can still ping other devices on my network.

I assume this is down to the firewall now?
I redid the firewall rules according to :
[OpenWrt Wiki] Guest Wi-Fi using CLI
and
[OpenWrt Wiki] Guest Wi-Fi extras

My understanding is that they allow DNS and DHCP and block everything else, but doesn't seem to be working that way.

/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 'fda7:3fb0:0b70::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth1.1'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.30.248'
	option gateway '192.168.30.1'
	option dns '192.168.30.250 208.67.220.123 208.67.222.123'

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 '2 3 4 5 0t'

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

config interface 'guest'
	option proto 'static'
	option device 'br-guest'
	option ipaddr '192.168.10.1'
	option netmask '255.255.255.0'

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

/etc/config/firewall

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

config zone 'lan'
	option name 'lan'
	list network 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	option masq '1'

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

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'

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 network 'guest'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'

config forwarding 'guest_lan'
	option src 'guest'
	option dest 'lan'

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

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

config rule 'guest_fwd'
	option name 'Allow-guest-Forward'
	option src 'guest'
	option dest_ip '!192.168.30.248/24'
	option proto 'all'
	option target 'ACCEPT'

/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 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'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	option ra_slaac '1'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	option ignore '1'

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 dhcpv4 'server'

psherman · November 29, 2022, 12:17am

What's the intent of this rule?

To block that subnet, try adding this rule:

config rule
	option name 'block-30'
	list proto 'all'
	option src 'guest'
	list dest_ip '192.168.30.0/24'
	option target 'DROP'

This DHCP option wasn't working because of 2 mistakes....

it should be:

	list dhcp_option '6,10.1.1.23'

(note that it is list not option, and dhcp_option without an s at the end.

routerboy · November 29, 2022, 1:44am

I honestly don't really understand the rule, but it's from:
[OpenWrt Wiki] Guest Wi-Fi extras
In the section Restricting upstream access / Wireless AP
The note says: Allow guest clients to access the internet but restrict upstream access.

Got it about the DHCP option. I just need either the dhcp option or the upstream server, correct? They do the same thing essentially?

So I changed the firewall rule. Now things got a bit weird
SSHd into the router I can ping anything on the internal network and on the internet.
From the guest WiFi, I can ping anything except the dumb AP. Pinging 192.168.30.248 is unreachable, but everything else I try is successful!

Configs below again...
/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 'fdad:c130:bc47::/48'

config device 'lan_dev'
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth1.1'
	option ipv6 '0'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.30.248'
	option gateway '192.168.30.1'
	option dns '192.168.30.250 208.67.220.123 208.67.222.123'

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 '2 3 4 5 0t'

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

config device 'guest_dev'
	option type 'bridge'
	option name 'br-guest'
	option ipv6 '0'

config interface 'guest'
	option proto 'static'
	option device 'br-guest'
	option ipaddr '192.168.10.1'
	option netmask '255.255.255.0'

/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 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'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	option ra_slaac '1'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	option ignore '1'

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 dhcpv4 'server'

/etc/config/firewall

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

config zone 'lan'
	option name 'lan'
	list network 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	option masq '1'

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

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'

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 network 'guest'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'

config forwarding 'guest_lan'
	option src 'guest'
	option dest 'lan'

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

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

config rule 'guest_block'
	option name 'Block-guest'
	option src 'guest'
	list proto 'all'
	list dest_ip '192.168.30.0/24'
	option target 'DROP'

psherman · November 29, 2022, 2:16am

This is expected (and desired) behavior.

The fact that 192.168.30.248 was not reachable is actually not the block rule we've been working on... it is the fact that input = reject on the guest zone. So that is good.

Try changing the block rule to look like this:

config rule
	option name 'guest-block'
	list proto 'all'
	option src 'guest'
	option dest 'lan'
	list dest_ip '192.168.30.0/24'
	option target 'DROP'

the difference here is that we are specifying the destination zone.

They do not do the same thing... very different, in fact.

The upstream server is used by OpenWrt for DNS (you could alternatively specify other dns servers).

If you don't specify option 6 (DHCP advertised DNS servers), the DHCP server will advertise the OpenWrt device as the DNS server when it provides leases to client systems. This means that the OpenWrt router will get the request and forward it to the system's designated DNS server (in this case it will be the upstream one specified earlier).

Using option 6 allows the DHCP server to advertise other DHCP servers (such as public ones or direct to a preferred DNS server). The clients will then use those servers instead.

That said, option 6 does not guarantee that the client devices will actually use the specified servers (nor does omitting option 6) -- clients can be set manually (or have system defaults) to use DNS servers that are preferred by the user/application/system. If you want to block those, that require another firewall rule, and if you want to block/redirect (hijack), you use a slightly different method. This is fairly straightforward with standard DNS (port 53), but is much harder with DNS over TLS (DoT) or DNS over HTTPS (DoH) which use encryption like pretty much everything else (making hijacking impractical, and blocking becomes quite a bit harder).

routerboy · November 29, 2022, 4:06am

Thanks for all you help @psherman. Adding the zone did the trick. I also added in the dhcp option 6 and I do see the specified DNS servers on the clients now as well!

In case anyone is trying to make sense of everything, below are the final configs.

/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 'fd2e:fdc6:b3b7::/48'

config device 'lan_dev'
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth1.1'
	option ipv6 '0'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option hostname 'DumbAP'
	option ipaddr '192.168.30.248'
	option gateway '192.168.30.1'
	option dns '192.168.30.250 208.67.220.123 208.67.222.123'

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 '2 3 4 5 0t'

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

config device 'guest_dev'
	option type 'bridge'
	option name 'br-guest'
	option ipv6 '0'

config interface 'guest'
	option proto 'static'
	option device 'br-guest'
	option ipaddr '192.168.10.1'
	option netmask '255.255.255.0'

/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 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'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	option ra_slaac '1'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	option ignore '1'

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 dhcpv4 'server'
	list dhcp_option '6,192.168.30.250,208.67.220.123,208.67.222.123'

/etc/config/firewall


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

config zone 'lan'
	option name 'lan'
	list network 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	option masq '1'

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

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'

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 network 'guest'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'

config forwarding 'guest_lan'
	option src 'guest'
	option dest 'lan'

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

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

config rule 'guest_block'
	option name 'Block-guest'
	option src 'guest'
	option dest 'lan'
	list dest_ip '192.168.30.0/24'
	list proto 'all'
	option target 'DROP'

system · December 9, 2022, 4:07am

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