Hi! I found these config lines in a site (http://www.linux.com/howtos/Bandwidth-Limiting-HOWTO/install.shtml) wich are a good approach for security matters... As you can see, the comments already tell what they are supposed to do... #all our LAN users will be seen by external web servers #as if they all used Mozilla on Linux. :) anonymize_headers deny User-Agent fake_user_agent Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.6+) Gecko/20011122 I got this problem when i added these two lines to my squid.conf: parseConfigFile: line 16 unrecognized 'anonymize_headers deny User-Agent' parseConfigFile: line 17 unrecognized 'fake_user_agent Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.6+) Gecko/20011122' The first thing I looked that could be a problem is that there is no acl reffering to "User-Agent" and looks like the "anonymize_headers deny User-Agent" works this way. But in the configuration file on the site I didn't find any acl regarding "User-Agent" either. Thanks a lot.