librenms-librenms/html/pages/device/port/arp.inc.php

<?php

echo '<table border="0" cellspacing="0" cellpadding="5" width="100%">';
$i = '1';

foreach (dbFetchRows('SELECT * FROM ipv4_mac WHERE port_id = ?', array($port['port_id'])) as $arp) {
    if (!is_integer($i / 2)) {
        $bg_colour = $list_colour_a;
    }
    else {
        $bg_colour = $list_colour_b;
    }

    $arp_host = dbFetchRow('SELECT * FROM ipv4_addresses AS A, ports AS I, devices AS D WHERE A.ipv4_address = ? AND I.port_id = A.port_id AND D.device_id = I.device_id', array($arp['ipv4_address']));

    if ($arp_host) {
        $arp_name = generate_device_link($arp_host);
    }
    else {
        unset($arp_name);
    }

    if ($arp_host) {
        $arp_if = generate_port_link($arp_host);
    }
    else {
        unset($arp_if);
    }

    if ($arp_host['device_id'] == $device['device_id']) {
        $arp_name = 'Localhost';
    }

    if ($arp_host['port_id'] == $arp['port_id']) {
        $arp_if = 'Local Port';
    }

    echo '
  <tr bgcolor="'.$bg_colour.'">
    <td width="160">'.formatmac($arp['mac_address']).'</td>
    <td width="140">'.$arp['ipv4_address'].'</td>
    <td width="200">'.$arp_name.'</td>
    <td>'.$arp_if.'</td>
  </tr>';
    $i++;
}//end foreach

echo '</table>';