socket.gethostbyaddr() question

[Steve Holden]

Harlin Seritt wrote:
> I have a list of IP addresses I am testing with socket.gethostbyaddr().
> For the most part, I am able to get a hostname returned to me when I
> run gethostbyaddr(). I am also hoping this will allow me to tell if a
> computer is up or down. However, in my environment, I am finding that I
> am able to get a hostname even though I am unable to actually ping that
> server (when I ping a server i like this, I get 'request timed out'
> messages telling me that the server is not up).
> 
> Other times, I am able to ping a server with success but the
> gethostbyaddr() request will not be able to return a hostname for me
> making me think that machine is truly down when I know it's not. Can
> anyone give me any pointers as to why this happens? Is there anyway I
> can do a reliable ping to another server with Python? I am not
> interested in doing system calls with a system Ping client (I have to
> ping way too many machines and this either takes too long or causes
> severe memory leakage due to MS's horrible ping client). Also, I am
> unable to use Jeremy Hylton's Python ping client because it does little
> more than call gethostbyaddr(). Thanks for taking a look at this.
> 
If  you have the ability to run code on the machines you are interested 
in you might want to consider Nicola Larosa's heartbeat recipe:

   http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52302

You may also find something useful in

   http://pynms.sourceforge.net/ping.html

regards
  Steve
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