Hello,
I've experienced many failures on wireless CPE/AP ethernet ports. The problem shows up going through different steps:
1) ethernet port stops working at 100Mbps/Full duplex but still work at 10 Mbps full/half dubplex
2) few days after step 1) the port stops working at all, stuck in down state (interface apeears not Registered in winbox).

It looks like routerboard are a little weak on ethernet hardware.
Anyone experiencing the same problem? How could I workaround ? Any trick in intallation phase to help saving the hardware (particular grounding, shielding, ... )?

Thanks

How long is the ethernet cable?
Have you checked cable with a tester?

If you running on Poe...
You should get prepare for this...

You can try and see, once you split the data and DC out, you problem will solve...

And try add DC protection before power go to the board...

Sent from my HTC Incredible S using Tapatalk 2

The most common cause for this is the quality of connectors and their crimping. Replace connectors with new ones and give a try. If you are sure they are fine and it is still happening, you probably have a faulty device connected to the other side of mikrotik. It has happened many times for me and it never was routerboard's fault. PoE has nothing to do with this.

The most common cause for this is the quality of connectors and their crimping. Replace connectors with new ones and give a try. If you are sure they are fine and it is still happening, you probably have a faulty device connected to the other side of mikrotik. It has happened many times for me and it never was routerboard's fault. PoE has nothing to do with this.

before we split out the poe + data, we on and off facing this issue...
after we spilt it out, over a year, there's no happened any more...

before we split out the poe + data, we on and off facing this issue...
after we spilt it out, over a year, there's no happened any more...

Thanks for your answers, still have some doubts: what do you mean for splitting out poe + data? Use 1 ethernet port just for poe and another one for data?
What if my device just has 1 ethernet port (i.e. wireless cpe) ? May you suggest me some DC protection products?

Thanks

before we split out the poe + data, we on and off facing this issue...
after we spilt it out, over a year, there's no happened any more...

Thanks for your answers, still have some doubts: what do you mean for splitting out poe + data? Use 1 ethernet port just for poe and another one for data?
What if my device just has 1 ethernet port (i.e. wireless cpe) ? May you suggest me some DC protection products?

Thanks

the simple way is using the RJ45 module to split it out...

Have you ever tried to use shielded FTP cable with shielded connectors, and a GROUNDED PoE ? For example the 15V or 24V from Ubiquiti works perfect for me.