title: bad request 400 with Telnet
body: <p>'m trying to use the If-Modified-Since command in Telnet. I want to get a 304 Not modified statut code. I tried this but it don't work, I get a 400 bad request error</p>
  
  <pre><code>telnet lemonde.fr 80
  
  GET /index.html HTTP/1.1
  User-Agent: Mozilla/5.0
  From: yahoo.com 
  Accept: text/html,text/plain,application/*
  Host: www.lemonde.fr
  If-Modified-Since: Wed, 19 Oct 2015 10:50:00 GMT
  &lt;linefeed&gt;
  </code></pre>
  
  <p>I got as a result </p>
  
  <blockquote>
    <p>HTTP/1.0 400 Bad request Cache-Control: no-cache Connection: close
    Content-Type: text/html</p>
  </blockquote>