Hello,
Recently I’ve getting problems with a setup, that due to it being a pretty common setup and the nature of the failure I’d like to share to see if anyone else’s got this issue and solved it.
Here’s the scenario:
Router: Mikrotik hAP Lite, Firmware first tested with 6.31 then 6.33.3
AP: Ubiquiti Nanostation Loco M2 first tested with firmware 5.5.8 then with 5.6.3
Configurations:
1.- The router’s got a bridge that joins the interfaces wlan1, ether2, ether3 and ether4. RSTP is active on this bridge, but tests were also done with STP and disabled.
2.- On this bridge there’s an IP address and also a DHCP Server, there’s also a Hotspot service running on the bridge (hotspot, ip address and dhcp server are placed pointing to the bridge, not the interfaces on it).
3.- The AP is set to bridge mode with WDS (also tried without WDS), airmax off, ip aliasing off (also tried with it on), cdp and discovery off (also tried setting it to ON), STP off (tried with it ON as well), multicast helpers off (tried on as well).
4.- The AP is connected to interface ether2 (tried on ether3 and ether4)
Here’s the problem.
Devices (laptops, smartphones) connecting through the AP don’t get IP addresses from the router. Checking the router’s log I can see the following:
A.- DHCP Discovery messages from the clients (with their corresponding MAC address as the source),
B.- Following the DHCP discovery the corresponding DHCP Offer from the router
C.- After that I can see the DHCP request from the client
D.- The router then responds this DHCP request with a DHCP NAK (and a DHCP lease failed message on router’s log)
If you do connect a device directly to the ethernet ports of the router, the device gets an IP address as it should, this would let to think that the issue is with the AP, the surprise comes when using any other router (on this case a generic brand from the ISP providing the connection) everything works as intended, connecting the AP with the same configuration used when connecting it to the hAP to the generic router switched ports allows the clients to get and IP address from the generic device…
Now, if I connect the AP to an interface not belonging to a bridge, add an IP address to said interface and then a DHCP server to it, everything works… clients do get an IP address from the router. The issue is always when using interfaces that belong to a bridge.
I’ve tried many different configurations on both the AP and the Router, but the result is always the same, as long the interface that the AP is connected to belongs to a bridge, clients connecting through the AP won’t get an IP address. This is really a basic and easy configuration, this issue shouldn’t be there, the only difference between a port belonging to a bridge and one that isn’t to my knowledge is Spanning Tree BPDUs, but I tested disabling STP on both devices and still doesn’t work.
Again:
1.- The AP bridge mode works as intended with devices from other brands
2.- The router provides IP address if you connect the device directly to the ethernet interface
3.- The router DHCP lease process will only work if the AP is connected to an inteface that’s not on a bridge port…
Has anyone experienced something like this before? if so, how did you solve it?