I'm a little confused. I have a client who has IIS Version 5 I believe which doesn't seem to produce the correct HTTP header as detailed by Google ... Can anyone point me in the right direction on how to implement this?

Here's the exact Technical Guidelines recommended by Google:

"Make sure your web server supports the If-Modified-Since HTTP header. This feature allows your web server to tell Google whether your content has changed since we last crawled your site. Supporting this feature saves you bandwidth and overhead"

Thanks for your help in advance.

Andrew Allfrey