I reinstalled my Raspberry, and I can access it with SSH, but it can't go outside of the router. How to debug it?
Modell: Raspberry Pi2 B+ OS: Raspbian
ip a to show your IP netstat -nr to check your Gateway is your Router. traceroute 8.8.8.8 to see if routing looks ok.
cat /etc/resolv.conf to see what nameserver is defined.
Although having said all this, you question isn't probably a good one for stackoverflow and you should be googling around something like 'connect raspbian to the internet' or 'raspbian network setup'