Re:F5 IRule (Score 0)

Users of Zeus Technology's ZXTM could use the following TrafficScript rule (which strikes me as slightly more intuitive):

if( http.getHeader("Accept-Encoding") == "" &&
    http.getHeader("Referer") == "" )
{
   $ua = http.getHeader("User-Agent");
   if( $ua == "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"||
       $ua == "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;1813)"||
       $ua == "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"||
       $ua == "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;1813)" )
   {
      connection.discard();
   }
}