title: What's the easiest way to test a gateway?
body: <p>I want to test a toy gateway I wrote. The testing will occur on Linux machines. I would like to do this in the easiest way possible, ideally writing no code and using existing utilities. This boils down to two questions:</p>
  
  <ol>
  <li><p>Is there an existing utility that can send packets with simple stuff in them(like a string that I supply) to a host through a user-specified gateway, without reconfiguring Linux's network settings? If so, what syntax would I use for the utility?</p></li>
  <li><p>Is there a simple utility I can run on the receiving end to verify that the correct packet was received? If so, what syntax would I use for the utility?</p></li>
  </ol>