Weird bridge behaviour on RB751U-2HnD

RouterOS Wireless Networking
1

Hi,

U’ve currently got a couple of RB751U-2HnD running both RouterOS 5.6 and 5.15 which we’ve been having some serious issues with.
Config in short; wlan1 is a station pseudobridge clone, added to a bridge where all the LAN ports are added as well. IP is set for the bridge.

We’ve got Computer1 which is connected by a switch to the gateway and a wireless AP, and Computer2 connected into to the RouterBox.

Everything is on the same IP range (10.0.0.0), but sometimes I’m only able to contact some of the equipment connected directly to the RouterBox, and not the RB751 itself. When I log in with Winbox and ping Computer1, I’m suddenly able to ping the RB751.


Anyone got any suggestions to why this keeps happening? Seems to happen with both RouterOS 5.6 and 5.15.

2

How are you logging into the winbox on the rb751 if you can’t contact it? Are you using mac-winbox to do so?

3

That’s the fun part.

I can remotely control Computer2, and access the RB751 through Winbox from that machine. Just a simple ping from terminal in Winbox to the gateway, and I’ll be able to connect directly to the RB751 again.

4

It seems like this might be caused by ARP problems.
The machines in the office are unable to ping any of the equipment connected to the RouterBoard until the equipment connected to the RB pings the office machines.

Ping from the RB-connected machines works just fine, so I assume this has to do with the way the RB redirects the pings sent to its MAC-address.

5

Hi,

These Problemsepends on the Wireless Mode you are Using!

Mistry7

6

The wlan1 is set to station psudobrige clone, and it’s set to clone the WLAN MAC of the RouterBoard.

7

Attached is a basic layout of our network. What would be the recommended WLAN mode for the RB751 in this case?
Layout.png

8

The current config on the RouterBoard:

/interface bridge
add l2mtu=1598 name=bridge1
/interface wireless security-profiles
set [ find default=yes ] group-ciphers="" unicast-ciphers=""
add authentication-types=wpa-psk eap-methods=passthrough group-ciphers=tkip management-protection=allowed mode=dynamic-keys name=profile1 supplicant-identity="" unicast-ciphers=tkip wpa-pre-shared-key=somekey
/interface wireless
set 0 band=2ghz-b/g country=norway disabled=no l2mtu=2290 mode=station-pseudobridge-clone rate-selection=legacy security-profile=profile1 ssid=SomeSSID station-bridge-clone-mac=00:0C:42:F8:F9:9D
/ip hotspot user profile
set [ find default=yes ] idle-timeout=none keepalive-timeout=2m
/interface bridge port
add bridge=bridge1 interface=wlan1
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=ether2
add bridge=bridge1 interface=ether3
add bridge=bridge1 interface=ether4
add bridge=bridge1 interface=ether5
/ip address
add address=10.0.0.30/24 interface=bridge1
/ip neighbor discovery
set wlan1 disabled=yes
/ip route
add distance=1 gateway=10.0.0.1
/queue interface
set ether1 queue=ethernet-default
set ether2 queue=ethernet-default
set ether3 queue=ethernet-default
set ether4 queue=ethernet-default
set ether5 queue=ethernet-default
9

When I manually add an IP and MAC address to the Computer 1’s ARP table it’s able to communicate with Computer 2 and Computer 3.
Could this be caused by the ARP setting for wlan1?

10

The mode you are using is only intended to bridge one device

See
http://wiki.mikrotik.com/wiki/Manual:Wireless_Station_Modes

Nick.

11

Hi, Nick, and thanks for the reply.

I did read the Wiki, and as far as I could tell from this sentence, station pseudobridge and station pseudobridge clone is to be used if the RouterBoard is bridged up against a non-RouterOS AP, or if only one end-user device is connected. As the RB is connecting to a non-RouterOS AP I assumed that this would work just fine.

The usage of this node can only be justified if AP does not support better mode for L2 bridging (e.g. when non-RouterOS AP is used) or if only one end-user device must be connected to network by means of station device.

Which mode is recommended, then?

12

Instead of bridging you could route.

You would use station mode on the RB751 and then either NAT the clients behind it, or route an extra subnet for them.

Nick.

13

If we were to remove one of the computers from the MikroTik, would pseudobridge clone work as it’s supposed to?

14

Could someone give me any pointers for the best configuration for this settings where only one computer is connected to the RB751U?