X-Robots-Tag: noindex & nofollow
Our indexing robots use the X-Robots-Tag in the HTTP page header and will not included pages in the search that are tagged with noindex and will not follow links in pages that are tagged as nofollow.
Please Note: This is not placed in between the head tags of the web page itself, but added to the HTTP header of your web server.
The nofollow part of the X-Robots-Tag is essentially out of date and you should be using the Anchor Tag NoFollow instead.
Examples:
X-Robots-Tag: noindex, nofollow
X-Robots-Tag: noindex
X-Robots-Tag: nofollow