Grab MAC From ARP Table With PHP

Cool function you can use on your local network to lookup a devices MAC address, (assuming the device is on your network), using PHP.

For a big company, either look in the remote locations router, or your core router.

// =============================================
// getmac(Device IP, Router, SNMP Read Community)
// Michael Requeny -- http://michael.requeny.com
// - Looks up remote devices MAC
// - SNMP to routers ARP table
// - Converts MAC from HEX to ASCII
// - Inserts : seperators
// =============================================
function getmac($ip, $router, $snmpread) {
	$oid = ".1.3.6.1.2.1.3.1.1.2";
	$mac = snmprealwalk($router, $snmpread, $oid, 1000000 ,10);
	// load up array keys for lookups
	$keys = array_keys($mac);
	foreach ($keys as $key) {
		// if needle contains IP && needle = IP
		// this prevents srch for 10.254.254.1 returning
		// multiple values (like .1, .11, .111, etc.
		if (strstr($key,$ip) == $ip) {
			$mackey = $key;
		}
	}
	$mac = trim(str_replace('Hex-STRING: ', '', $mac));
	$mac = str_replace(' ', ':', $mac);
	return $mac;
}