RB5009 LAN port down/up state

RouterOS Beginner Basics
1

Hey everyone. Just bought a rb5009ug+s+in. Firmware and routerOS are both on 7.7. Small issue I’m having and having trouble finding anything on the forums. Every 10 mins my lan port goes into a link down, then up state, disconnecting me from winbox and dropping internet to that port. I’m using ppooe login for CenturyLink fiber with vlanID 201. Has anyone seen anything that could potentially fix this issue? My cat5 cable is confirmed working. I tried ether2 and ether 3,4,5,6,7,8 ports to rule out a fouled port. Out of ideas and I am not ready to fully deploy the router yet until this issue is corrected. Thanks.

Tried 3 different working cat5e cables. tried different ports on the router.



TIA

2

Try disabling Auto Negotiation on your LAN port and setting it to 1Gbps

3

I did that as well. Set it to 1gb. It dropped faster. Within 3 mins or instantly.

4

Hey, the same issue occurred with mine MIkrotik 5009. Did find out the root cause?

5

Just posting in hopes it will help someone in the future. I purchased RB5009UG+S+in. I had set up my WAN port on ether1 (2.5 Port) and attached my LAN on ether2 (1GB Port). Very simple configuration with a dhcp being served by the router. Everything was working but every 10 minutes or so the I would lose connectivity. I checked the logs and it was exactly as described above. My ether2 port kept going down then immediately come back up. I tried disabling Auto Negotiation on the Lan port. I adjusted the dchp settings. Nothing worked. The device attached to ether2 was a ScreenBeam MoCa 2.5 network adapter. It was attached through coaxial to 2 other MoCa 2.5 adapters. I Moved my WAN port to ether5 (1GB Port) and moved my LAN port to ether 1 (2.5 Port). It has been 24 hours and both ports have remained connected. I am assuming the router and the MoCa device were not able to negotiate to 1GB or the MoCa device kept trying to negotiate to a faster speed.

6

Thanks mate, got exactly the same issue with MoCA and RB5009UG! Will try your solution now!

7

Thanks again! It started to work as expected. You saved me a lot of hours )

8

Ran into a similar issue with my RB5009UG+S+IN and a pair of G4201TM G.Hn modems from GIGA Copper Networks. Kept getting random freezes in video calls, video games and game streaming when going through the modems to the router. Eventually discovered the port the modem was plugged into kept dropping then a few seconds later reconnecting which coincided with the freezes. Found this thread and switched my WAN port to one of the 1Gpbs ports and used the 2.5Gbps port for the modems. Seems to be working fine now! Weird problem.