Mikrotik routers are great hardware. With one you can mirror traffic that go thru on so you will be able to sniff trafic as you would being directly connected between target and router (or behind one)
#enable sniffing tool
/tool sniffer set streaming-enabled=yes streaming-server=ip.you.will.operate
/tool sniffer start
This way you can run tool like wireshak on your computer (the ip you put as streaming-server) and look thru it.
Remamber that mirrored traffic will be transported as TZSP (udp port 37008)