Torch to monitor traffic

I know how to use torch to monitor traffic on an interface.

I want to have is a portable 750 routerboard I can carry with me and plug
into a network to see where and how much traffic on the network.

Question is how would I configure my RB750 so that I can just place it inline
using two ethernet cables and look at the traffic? I prefer not to have to setup
up ip networks. Can I just bridge two ethernet ports and use them for my
in and out and torch that bridge?

Thanks.

I figured it out. First I configured ports ethernet 4 and 5 with master to none.

Then I set up a bridge between ethernet ports 4 and 5 with firewall rule to pass
all traffic.

Then I took the ethernet cable with my network traffic on it and plugged it into port
4 on the 750 router. Took another ethernet cable, plugged one end into port 5 and the
other end into my original router.

Then I can torch port 4 and or 5 and see the connections and traffic.

Maybe this will help someone else in the future.