VLAN Issue after firmware upgrade

Hello everyone.

I’ve got the following setup on a Mikrotik RB2011UiAS-RM router. (Firmware: 6.36)

The router is connected to a trunk port on the switch and all the VLAN interfaces are configured on the router.

Dell N2024 switch, port 24 (trunk) ------> Mikrotik, ether2

All VLAN interfaces are configured on ether2 and gateway IP address on the VLAN interfaces.

[admin@router-orkd] > /interface vlan print 
Flags: X - disabled, R - running, S - slave 
 #    NAME                     MTU ARP        VLAN-ID INTERFACE                  
 0 R  v171-srv                1500 enabled        171 ether2                     
 1 R  v161-camda              1500 enabled        161 ether2                     
 2 R  v162-wifi               1500 enabled        162 ether2                     
 3 R  v163-lan                1500 enabled        163 ether2                     
[admin@router-orkd] >



[admin@router-orkd] > /ip address print 
Flags: X - disabled, I - invalid, D - dynamic 
 #   ADDRESS            NETWORK         INTERFACE                                
 0   172.16.1.254/24    172.16.1.0      v161-camda                              
 1   172.16.2.254/24    172.16.2.0      v162-wifi                               
 2   172.16.3.254/24    172.16.3.0      v163-lan                                
 3   10.1.1.2/30        1.1.1.0         sfp1                                     
 5   172.16.0.254/24    172.16.0.0      ether2            
 6   172.17.1.254/24    172.17.1.0      v171-srv                                 
[admin@router-orkd] > 

Note: ether2 has an IP configured on the interface to enable communication to untagged vlans (vlan1) on the switch.

Everything was working fine, the inter-vlan routing worked great until I upgraded to the latest firmware from v6.35.1 to v6.36. After rebooting the router wasn’t able to communicate to any VLAN and devices on switch couldn’t reach the gateway IP on the router.

In a previous setup with a different model of switch I noticed that I would need to create a bridge and assign vlan and physical port to the bridge to enable traffic on the default vlan 1 due to the how the switch handled traffic on the default vlan.

So I created a bridge, assigned port ether2 to it… and all of the sudden the inter-vlan routing starts to work. And the weird thing is disabling the bridge afterwards doesn’t seem to effect the vlan communications. Traffic continues to work as if the bridge isn’t required. But after a reboot, once again the same thing happens where the router isn’t able to communicate.

I’d really appreciate if someone here can explain what is actually happening here? Is it a bug? Or is my configuration incorrect?

Thanks