Anti-Terrorism Methods in the Delorie Counter

Counter Terrorism is a term for any malicious use of a counter, most likely an attempt to increment the counter wildly without corresponding actual page accesses. There are many ways to deal with it, and here are the ones that the Delorie Counter uses.

• Ignoring known offenders - if you know the host name that the attack is coming from, you can put it in your control file with an ``ignore'' command. Accesses from that host will not increment the counter.

• Ignore repeats - If one client accesses your counter multiple times in a row, it only counts as one ``hit''. The chances of an attacker having two spam-programmable machines available are pretty low.

• Ignore unreferred hits - If the request does not come with a valid referrer, it assumes that the access was generated by something other than an IMG tag. This is, of course, easily circumvented.

• Ignore remote referrals - If a web page from some other server uses your counter in an IMG tag, they won't increment the count.