Monitor Home Internet/Network I.P. requests/packets

I apologize for the title being all over the place, not sure how to ask the right questions.

I am trying to monitor the traffic on my home network in real time. Basically I have an old laptop I would like to setup, have some sort of console up and see the traffic/packets/requests going over the network. Why?

1. I am getting DDoSed while playing games and want to be able to see what I.P.(s) are sending the requests/traffic.


2. I want to make sure someone in our neighbourhood isn't on our network.

I am pretty tech savvy so even just pointing me to an article would help a ton.

Thanks

P.s. If I can't do it live, can I check a log file (similar to a web server)?