Hello,
I'm using CRS125-24G-1S-2HnD router and I need to install sniffer-host in my network. I was trying with Packet Sniffer but that method is using a lot of cpu.
How can I configure port mirroring on that router to sniffing on another machine?

For mirroring a port please refer to:

https://wiki.mikrotik.com/wiki/Manual:C ... _Mirroring