DHCP Issues on RUTC50: IP Assignment in Dual AP Setup

[egothor]

I’m new to this ecosystem and working on configuring my RUTC50 router.

I’m setting up two access points: (a) a 5GHz network with WPA2/RADIUS, and (b) a 2.4GHz network with WPA2 PSK. Both networks have DHCPD enabled for clients, but only (a) is successfully delivering IP addresses. For (b), I can only connect clients using static IP configurations.

I’ve noticed that on the br-ifLan1 interface (see below), I can see DHCP requests from clients, but no responses.

Currently, I have two LANs, two SSIDs, and the corresponding DHCPD setups. I’m unsure what might be wrong with the configuration. Could you suggest a correct setup? I suspect that the Teltonika router may not be able to listen on two interfaces simultaneously, making my desired configuration unworkable. Thank you in advance.

My interfaces:
lan: Wifi 5GHz + lan{1-4}; 192.168.1.1/24 (br-lan)
wifi_trap: Wifi 2.4GHz; 192.168.2.1/24 (br-ifLan1)

Snippets of configuration:

config/network:

config interface 'ifLan1'
	option name 'wifi_trap'
	option area_type 'lan'
	option device 'br-ifLan1'
	option proto 'static'
	option igmp_snooping '0'
	option ipaddr '192.168.2.1'
	option netmask '255.255.255.0'
	option delegate '1'
	option force_link '1'
config device 'br_ifLan1'
	option name 'br-ifLan1'
	option type 'bridge'
	option stp '0'

dnsmasq (auto-generated config):

interface=br-lan

dhcp-range=set:lan,192.168.1.100,192.168.1.249,255.255.255.0,12h
dhcp-range=set:ifLan1,192.168.2.100,192.168.2.249,255.255.255.0,12h

br-ifLan1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc cake state UP group default qlen 1000
    link/ether 20:XX:XX:XX:XX:XX brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 brd 192.168.2.255 scope global br-ifLan1
       valid_lft forever preferred_lft forever

[egothor]

When I see so much SPAM on this forum, I’d rather buy Cisco or Mikrotik products that work flawlessly and come with reliable support

[Janmiguel]

Hi egothor,

Thank you for your understanding and patience.

If you want devices connected to 2.4GHz Wi-Fi to a different subnet (i.e. 192.168.2.0/24), you need to assign atleast one LAN port to that subnet.

First, create a VLAN (i.e. VLAN 10)

Then under LAN, add another interface (i.e. lan2). Input the subnet and make sure to enable DHCP.

On the same instance. go to Physical Settings and assign the created VLAN in the interface.

Lastly, go to settings of 2.4 GHz Wi-Fi and change network to lan2.

Once an end device is connected to 2.4 GHz Wi-Fi, it should be assigned within the 192.168.2.0 subnet pool.

Let me know if this helps.

Regards,

[egothor]

In other words, it suggests that expensive Teltonika routers cannot run two independent DHCP daemons on two different bridges. The workaround is to route all requests to a single DHCP instance, which might be aceptable if one could not configure two independent bridges via the admin interface and enable DHCP on both. Teltonika should either disallow configuring two separate bridges with independent DHCP daemons or, ideally, ensure the (web) configuration translates correctly in the back end. Other competitors are able to do so even for cheap $50 units.

This is fundamental flaw: the web interface allows certain configurations that are not properly supported by backend! It is surprising for a $500 unit. I am really shocked.