I'm trying to build a tracking server for banner ads that tracks the ad's impressions. I'm having some trouble with our accuracy. It appears we're missing maybe 20% of the impressions. I'm using a tracking pixel gif resting on a lighttpd web server. I have implemented anti-caching methods via a unique number attached to the URL of the gif. I have a cronjob set to parse the access log for the gif and enter the totals for that period into a database row, and clear the log.
Anyone know any other method of accurately tracking high volumes of impressions? Preferably using a gif file which can be loaded within a flash swf?