I have a RB1200 that I am using in a pinch to do some rate limiting and ip blocking on both side of a cisco asa (dont ask).

On the RB1200 I have
ports 1-2 bridged
and 9-10 bridged
Ether1 Plugs into Cisco edge router
Ether2 plugs into ASA WAN
Ether9 Plugs in to ASA Lan
Ether10 plugs into internal switch

One thing to note is that none of the cisco ports would auto negotiate FD, so all four ether had to be set to 100fd manually

Yesterday my alarm went off that the ASA would not ping on wan. I went to the location and discovered that all four lights on the ether interfaces of the RB1200 were not lit, I plug in laptop to port 3 and it lit but would not find anything in winbox ...

I rebooted the router, no beeps, same result. Reboot again, everything fires up. I put on a watchdog, and uploaded ROS 5.6 (but did not load it yet, waiting till after hours), so far no more problems.

Any Ideas what happened? I have a stack of RB1200's to install and must rely on the them.

Please check if the same issues are present on MikroTik RouterOS v5.6 and latest RouterBOARD firmware (/system routerboard upgrade and /system reboot to upgrade it).

I have upgraded (I was waiting till late night) and nothing odd has happened. I will updated this thread if it happens again.

Ok this happened again with ROS V 5.6 . Also the Watchdog did not reboot the the system and I did not get a supout.

This happened again on a completely different RB1200 running 5.2 with a completely different setup. The box locked up and all ether ports went dark. This unit had nothing configured except ports 1,9,10 were in a mesh and the mesh has an IP.

Please contact MikroTik support (support@mikrotik.com) and attach support output file from your router.
Include problem description too.