How to block Googlebot quickly?

I see you are currently trying to use glob-patters in your robots.txt.

From The web robots page:

Note also that globbing and regular expression are not supported in either
the  User-agent or Disallow lines. The '*' in the User-agent field is a 
special value meaning "any robot". Specifically, you cannot have lines like 
"User-agent: *bot*",     "Disallow: /tmp/*" or "Disallow: *.gif".

You would either need to do what Arenstar or Tom O'Connor recommend (that is, use an Apache ACL to block them, drop the traffic at the IP level) or, possibly, route the IP addresses via 127.0.0.1 (that'd stop them from establishing TCP sessions in the first place).

Long-term, consider if you can place all your CPU-intensive pages under a common prefix, then you'll be able to use robots.txt to instruct crawlers to stay away from them.

Use a robots.txt file in your document root directory firstly.. Spiders and Bots normally look for this file before beginning the scan..

Use a .htaccess file ( this could also be put in your apache configs, though needs syntax change )

   RewriteEngine on
   RewriteCond %{HTTP_USER_AGENT} ^googlebot
   RewriteRule ^(.*)$ http://google.com/

http://www.besthostratings.com/articles/block-bad-bots.html

Hope this helps.. :D

If you know the googlebot's IP address, you could set a DROP rule in iptables, but that's a real hack.

iptables -I INPUT -s [source ip] -j DROP

where [source ip] is the googlebot's IP.

This'd definitely stop them, instantly, but it's a bit.. low level.

To unblock

iptables -D INPUT -s [source ip] -j DROP

Assuming you don't actually want your site delisted from Google (which the accepted answer will eventually cause) set a crawl delay value for your site in Google Webmaster Tools. It is reported that Google does not support Crawl-Delay in robots.txt, though you may wish to set that value for other search engines and crawlers to use.

We wanted to block a specific directory from robots. We had a robots.txt entry but it's being ignored by many robots. So we added this snippit below to our apache configuration file; note that we uncommented the Wget because we wanted to allow that. It works by blocking based on the HTTP_USER_AGENT.

The list comes (obviously) from http://www.javascriptkit.com/howto/htaccess13.shtml; when we modify configuration files with information we get from the Web we always put the back-pointer so we know where it came from.

    <Directory "/var/www/domaintoblock/directorytoblock/">

            # Block bots; from http://www.javascriptkit.com/howto/htaccess13.shtml                    
            # Note that we allow wget                                                                 
            RewriteEngine On
            RewriteCond %{HTTP_USER_AGENT} ^BlackWidow [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Bot\ mailto:[email protected] [OR]
            RewriteCond %{HTTP_USER_AGENT} ^ChinaClaw [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Custo [OR]
            RewriteCond %{HTTP_USER_AGENT} ^DISCo [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Download\ Demon [OR]
            RewriteCond %{HTTP_USER_AGENT} ^eCatch [OR]
            RewriteCond %{HTTP_USER_AGENT} ^EirGrabber [OR]
            RewriteCond %{HTTP_USER_AGENT} ^EmailSiphon [OR]
            RewriteCond %{HTTP_USER_AGENT} ^EmailWolf [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Express\ WebPictures [OR]
            RewriteCond %{HTTP_USER_AGENT} ^ExtractorPro [OR]
            RewriteCond %{HTTP_USER_AGENT} ^EyeNetIE [OR]
            RewriteCond %{HTTP_USER_AGENT} ^FlashGet [OR]
            RewriteCond %{HTTP_USER_AGENT} ^GetRight [OR]
            RewriteCond %{HTTP_USER_AGENT} ^GetWeb! [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Go!Zilla [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Go-Ahead-Got-It [OR]
            RewriteCond %{HTTP_USER_AGENT} ^GrabNet [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Grafula [OR]
            RewriteCond %{HTTP_USER_AGENT} ^HMView [OR]
            RewriteCond %{HTTP_USER_AGENT} HTTrack [NC,OR]
            RewriteCond %{HTTP_USER_AGENT} ^Image\ Stripper [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Image\ Sucker [OR]
            RewriteCond %{HTTP_USER_AGENT} Indy\ Library [NC,OR]
            RewriteCond %{HTTP_USER_AGENT} ^InterGET [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Internet\ Ninja [OR]
            RewriteCond %{HTTP_USER_AGENT} ^JetCar [OR]
            RewriteCond %{HTTP_USER_AGENT} ^JOC\ Web\ Spider [OR]
            RewriteCond %{HTTP_USER_AGENT} ^larbin [OR]
            RewriteCond %{HTTP_USER_AGENT} ^LeechFTP [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Mass\ Downloader [OR]
            RewriteCond %{HTTP_USER_AGENT} ^MIDown\ tool [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Mister\ PiX [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Navroad [OR]
            RewriteCond %{HTTP_USER_AGENT} ^NearSite [OR]
            RewriteCond %{HTTP_USER_AGENT} ^NetAnts [OR]
            RewriteCond %{HTTP_USER_AGENT} ^NetSpider [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Net\ Vampire [OR]
            RewriteCond %{HTTP_USER_AGENT} ^NetZIP [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Octopus [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Offline\ Explorer [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Offline\ Navigator [OR]
            RewriteCond %{HTTP_USER_AGENT} ^PageGrabber [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Papa\ Foto [OR]
            RewriteCond %{HTTP_USER_AGENT} ^pavuk [OR]
            RewriteCond %{HTTP_USER_AGENT} ^pcBrowser [OR]
            RewriteCond %{HTTP_USER_AGENT} ^RealDownload [OR]
            RewriteCond %{HTTP_USER_AGENT} ^ReGet [OR]
            RewriteCond %{HTTP_USER_AGENT} ^SiteSnagger [OR]
            RewriteCond %{HTTP_USER_AGENT} ^SmartDownload [OR]
            RewriteCond %{HTTP_USER_AGENT} ^SuperBot [OR]
            RewriteCond %{HTTP_USER_AGENT} ^SuperHTTP [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Surfbot [OR]
            RewriteCond %{HTTP_USER_AGENT} ^tAkeOut [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Teleport\ Pro [OR]
            RewriteCond %{HTTP_USER_AGENT} ^VoidEYE [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Web\ Image\ Collector [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Web\ Sucker [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebAuto [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebCopier [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebFetch [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebGo\ IS [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebLeacher [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebReaper [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebSauger [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Website\ eXtractor [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Website\ Quester [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebStripper [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebWhacker [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WebZIP [OR]
            #RewriteCond %{HTTP_USER_AGENT} ^Wget [OR]                                                
            RewriteCond %{HTTP_USER_AGENT} ^Widow [OR]
            RewriteCond %{HTTP_USER_AGENT} ^WWWOFFLE [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Xaldon\ WebSpider [OR]
            RewriteCond %{HTTP_USER_AGENT} ^Zeus
            RewriteRule ^.* - [F,L]
</Directory>