It is the same as your gateway because that is the default when you are using DHCP to pull your IPs from your router. Your router is most likely set to DHCP to get it's address from the ISP The DNS is provided through your router. Your router is your gateway because it will forward your requests to the next hop. The router is your DNS because all of your DNS requests will be forwarded through your router. You can type in static information if know the IP network you are on and the specific DNS server addresses.