title: Access IPV6 with IPV4
body: <p>Sorry for my poor title.</p>
  
  <p>Here is my situation：
      Our lab has a centos server  which has an local ipv4 addr  10.x.x.x and an public ipv6 addr.</p>
  
  <p>I also have a ramnode server which has a public ipv4 addr and a public ipv6 addr.</p>
  
  <p>And I only get an ipv4 addr at home, the question is how can I access the centos server using the ramnode ?</p>