Obviously using this option only makes sense if you choose a
limit below the one enforced by the operating system.
+
+
One most POSIX-compliant systems Privoxy can't properly deal with more than
+ FD_SETSIZE file descriptors at the same time and has to reject
+ connections if the limit is reached. This will likely change in
+ a future version, but currently this limit can't be increased
+ without recompiling Privoxy
+ with a different FD_SETSIZE limit.