how to identify web crawlers of google/yahoo/msn by PHP?

Question

AFAIK,

$_SERVER[\'REMOTE_HOST\'] should end up with \"google.com\" or \"yahoo.com\".

but is it the most ensuring method?

any other way out?

Answer 1

You are probably better off using $_SERVER['HTTP_USER_AGENT'] and look for Googlebot or Yahoo! Slurp.