Unwanted Traffic appeares on SFP1

[BartoszP]

Hi,

Welcome on the Forum.

What about packet inspection using Wireshark or any other external to MT monitoring tool?
Do you see that traffic on Cisco interface?

And finally: it would help if you provide config of the MT device:

Forum rules

If you are new here - welcome! For your first question, please provide a clear description of your setup, make sure you are running the latest RouterOS version and include the configuration output. You can censor out passwords and such, but posting the config is important. Do respect the forum regulars, this is not an official support platform, but a forum that is run by volunteers on their own free time. Posting large setups “for evaluation” might not get you any answers, so start with the core…

particulary post #5

Forum rules

Hello and welcome to the Mikrotik forum For all new users that uses RouterOS for the first time and have some questions regarding their config here is short tutorial on how to access RouterOS configuration using "WinBox" and how to export their configuration and posting it properly in their topic. So after you unpack your new device and connect it to the power supply you need to connect it to the PC. Be careful when connecting because to access your new router you need to use one of…

We do not know even the model you use.