limit_zone: Using other variables than $binary_remote_addr

[Steffen Weber]

One further question: Can I somehow prevent that the requests denied by 
limit_zone end up in my access log? Some download managers are quiet 
aggressive and flood the log.

It would be okay if all requests denied with a 503 response code were 
not logged. I think this should be possible by making the "access_log" 
directive conditional (using an if clause). But I have not found a 
suitable variable that I could use in the conditon.

Steffen