RAS and DNS Communication

User(Laptop) when he connecting from home through RAS he is not able to access internet/intranet. When user connects to RAS, he gets automatically IP Address and DNS server IP from RAS server.As we checked DNS IP was 10.X.X.X however it is not pinging that’s why user is unable to connect internet. How can i know from client which RAS server he is connecting to ? and can we make any changes in the server ? how we can check on our RAS server why the computer is picking this DNS automatically ?