Limit_conn with zones -- safe production server value?

[pk899]

Hi. I am trying to replicate the functionality of mod_evasive on Apache,
which basically says that at the same point the same IP can have only "X
connections per second". 

I see the example here: 
http://wiki.nginx.org/HttpLimitZoneModule

But this uses "binary_remote_addr". How does this cater for shared IPs,
where people in the same network may actually have the same remote addr.


Can I therefore use some other variable, such as a combination of
"binary_remote_addr" and their "http_user_agent"? 

What is the most often used value in production environments? 

Thanks!

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,202012,202012#msg-202012