Ping? or, just find if an IP is in use?

[Anon]

Is there a simple way to ping an IP address in PHP? I dont necessarially need to ping, just to see if the IP is in use. I figured doign a socket open to that IP would not be the best route, but I am open to suggestions.

[brandonschnell]

might as well ping the ip.

<?

$a = "127.0.0.1";

$results = ping -c 2 $a;
#echo $results; #uncomment to see what ping actually returns
if (stristr($results,"bytes from")) #look for a string that ping only returns when its successful
echo "ip is in use";
else
echo "ip is not in use";
?>

[[deleted]]

If a PING does not return any results that does NOT mean that an IP number is not in use. It only means that PING did not receive an answer from a computer with that IP number.

This could have any of a hundred reasons. (server down, firewall blocking, routing error, NAT)

But, if PING can get a reply from the remote server, the IP is in use.

[Anon]

Thanks everyone. For what I am doing, more of a maintenance script and not something that runs on a web server, this should work. Too bad there isnt something built into PHP though (since here you are just executing an external command).