So I (had) a friend who now hates me and he said he would take me offline if I blocked him on Skype. I did not believe him and I said "I don't care, do your worst". Big mistake - he found out my IP address and he is now DDoSing me. I really didn't think he would be able to do it, I thought that my ISP has some sort of filter and protection against this, and that my friend was not smart enough to take me offline.
I am using an Xfinity 2 in 1 modem/router.
How can I find out the IP address of the person DDoSing me?