Hello!

Really need help with the problem.

Some sort of strange problem could this be a hardware failure ?

There is a RB2011UAS-2HnD-IN with following configuration:
eth2-eth10 ports and wlan port configured in bridge (no firewall) eth1 configured for wan
Simple firewall with nat and hairpin nat rules.


Everything was working fine until a few days ago.
There is a random packet loss on a random clients.

The bug:
When I ping router internal ip everything is ok.
When I do ping external ip (for example 8.8.8.8 ) from LAN client there is no response I turn torch on the port I'm connected directly and I see tx packets from my ip, and 0 rx packets.
I turned torch on bridge interface and I see only winbox packets on my ip no other packets.

Then I ping my ip from router and after that there is a tx/rx packet on eth and bridge interfaces. And everything started to working for my PC. Reboot router and everything is not working again.
For other clients connected over wifi when I ping them from router they receive some packets from external ip during this time.

There was no configuration changes. I update to latest RouterOS 6.42.1. Made reset and restore but nothing changed. There is no high cpu load on device.

Any reason packets could disappear on bridge interface ? the problem is not with bridge interface see below

After router reboot it's almost always not possible to connect to router using winbox I can login only after many attempts.

update:
I turned bridge off and connected external switch to make same function and nothing really changed. Packets can be seen on eth port but lost after that. So the problem is not with bridge but with transferring packets from port to somewhere else in packet flow.

Also when I ping router internal ip it's always ok there is no packet loss but I don't see this packets in torch on this port.

This is very silly but there was another device plugged into network (another router I suppose) and it was spoofing router ip so that some clients connect to it sometime (I was told there were no changes). but I have to make a x86 box with router OS to find this.

I suppose this could be seen very fast on regular linux/bsd box on dmesg. I wonder if there are any similar tools in routeros ?