title: How to detect router?
body: <p>I am trying to write a program that scan an ip range and detect if an ip is address of a router or not. </p>
  
  <p>Currently i used traceroute from my computer to all host in the network. However, i believe there must be some way to directly "ask" a host at an ip if it is a router or not?</p>
  
  <p>by the way, do you know any program/ opensource already does this?</p>