ModRewrite lookups

[miless]

Does ModRewrite perform a useragent lookup for each banned useragent or does it lookup the useragent just once and uses that lookup to check the banned useragents ? I'm asking this to see if this method is efficient, if not I would write some PHP instead.

 

RewriteEngine on
RewriteRule ^403.html$ - [L]
RewriteCond %{HTTP_USER_AGENT} ^useragent1 [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^useragent2 [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^useragent3 [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^useragent4 [NC]
RewriteRule ^.* - [F,L]