View an Example of this article before you get started.

Recently I had a need for a script that would verify a server was online. I decided to write a simple function for just that and am now making it into a tutorial for others to benefit from. The overall script is simple, it pings the server and reacts based on the result.

Okay, start by creating the function.

function verifyRemoteServerOnline($server, $port)
{

}

The checking of the server will be accomplished by using fSockOpen which is included in the standard installation of PHP. This will verify the server and port specified is online.

function verifyRemoteServerOnline($server, $port=null)
{
	if(is_null($port))
	{
		$port = 80; // default Apache port
	}

	$sock = @fSockOpen($server, $port, $err_no, $err_str, 30);
}

Now once we have the socket established lets see if its valid.

function verifyRemoteServerOnline($server, $port=null)
{
	...
	
	return (!$sock) ? false : true;
}

Thats it, like I said in the beginning, its a pretty simple script.

Here is the full script.

function verifyRemoteServerOnline($server, $port=null)
{
	if(is_null($port))
	{
		$port = 80 // default Apache port
	}

	$sock = fSockOpen($server, $port, $err_no, $err_str, 30);
	
	return (!$sock) false : true;
}

Here is a quick example.

$server = "scriptplayground.com";
$port = 80;

if(verifyRemoteServerOnline($server, $port))
{
	print $server . " is online.";
}
else
{
	print $server . " seems to be offline. May need further investigation.";
}

I hope you enjoyed this tutorial. As always, if you have comments or questions, please post them below.