Avoid using characters like (0,o,O,1,i,l) in generating random passwords.

non-ambiguous_password.php

<?php
function randomPassword($length = 6) {
	// Non-ambiguous chars
	$alphabet = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789';
	$alphamax = strlen($alphabet) - 1;

	$password = '';
	for ($i = 0; $i < $length; $i++) {
		$password .= $alphabet[mt_rand(0, $alphamax)];
	}

	return $password;
}