Yes but characters in args like = & and ? are allowed and its when they insert more than one occurance of them nginx accepts them and they bypass any caches that you have.

&argument=value | Cache : HIT

&&&arguement===value | Cache : MISS


And when they want to DoS you they will do something like the following.


?random=1
?random=2
?random=3
etc etc

It is easy to bypass the cache when your not suppose to.

http://www.networkflare.com/