title: Query reverse dns lookups with dnspython
body: <p>I am trying to query reverse lookups in dnspython. Unfortunately, the from_address() function does not let me hand over a IP by variable. Any ideas why?</p>
  
  <pre><code>#!/usr/bin/env python
  
  import dns.resolver,dns.reversename
  
  with open("test", "r") as ips:
      for ip in ips:
          ip = str(ip)
          n = dns.reversename.from_address(ip)
          print str(dns.resolver.query(n,"PTR")[0])
  </code></pre>
  
  <p>I am new to python; would be great if somebody could help out!</p>