freebsd stable - May 2008 - how much memory does increasing max rules for IPFW take up?

I had a box run out of dynamic state space yesterday.  I found I can  
increase the number of dynamic rules by increasing the sysctl  
parameter net.inet.ip.fw.dyn_max.  I can't find, however, how this  
affects memory usage on the system.  Is it dyanamically allocated and  
de-allocated, or is it a static memory buffer?

Thanks!

Vivek Khera wrote:
> I had a box run out of dynamic state space yesterday.  I found I can 
> increase the number of dynamic rules by increasing the sysctl parameter 
> net.inet.ip.fw.dyn_max.  I can't find, however, how this affects memory
> usage on the system.  Is it dyanamically allocated and de-allocated, or 
> is it a static memory buffer?
Each dynamic rule allocated dynamically. Be careful, too many dynamic 
rules will work very slow.

-- 
WBR, Andrey V. Elsukov

How are the buckets used?  Are they hashed per rule number or some  
other mechanism?  Nearly all of my states are from the same rule (eg,  
on a mail server for the SMTP port rule).

How should I scale the buckets with the max rules?  The default seems  
to be 4096 rules and 256 buckets.  Should I maintain that ratio?