Not too long along we had some bad weather and my whole network took a knock. ADSL router got fried and the CPE on my side of the wireless bridge also died. So I replaced both with the CPE getting a shiny new RB411.

Now like 5 months on, all is running well. Last week I noticed that Port 1 on my router has a yellow light and not green. All other ports have green lights. Now I knew this meant that speed was no longer 100Mbps but 10Mbps.

I swapped ports, rebooted the routerboard and even reset my router to factory default. All to no avail.

Once logged into the routerboard with Winbox I checked the interface settings. The ethernet port had auto-negotiation turned on and of course everything looked okay. Except that it was confirmed that the connection speed was only 10Mbps.

Now I did some transfer tests and 10Mbps is still fast enough...for now. In South Africa we only still have 4Mbps ADSL main stream but 10Mbps is due this month. Inevitably ADSL2+ is coming and then 10Mbps on the CPE is going to bottleneck my network.

Is there anything I can do short of returning the routerboard under warranty?

RB411 have only one ethernet port. Can you test it with other device like PC , laptop or fast ethernet swich.

You mean winbox into the RB411 direct from my PC, bypassing the ADSL router? Yeah, I guess I can do that. I was just wondering how something like this all of a sudden happens. I came to the conclusion that the RB411 is most probably faulty, what else could it be?

You probably had bad weather again. If you have a bad power supply, or improper grounding, the Ethernet chip can get damaged, either completely or to 10 Mbps, from ESD.

Just to update on this topic.

It was by chance that I discovered the root cause because I was not really bothered to return the routerboard due to the downtime that would result. A few weeks later, some of my other ports on my router starting going yellow. Only 1 port would work on green but even if I tested the routerboard on that port, it would not work on green.

Because my Netgear router was now the likely suspect, I had it swapped out and all ports are green/full speed again. Seems my DGN2000 ADSL router was about to fall over.

So false alarm, not a Mikrotik problem!

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