IPFW what is dynamic buckets in ipfw ?

[miky]

Hello,

I think I have problems with ipfw running on my server. But my post is not about that, I would like to understand the parameters.

I have

# sysctl -a | grep buckets
net.inet.ip.fw.curr_dyn_buckets: 256
net.inet.ip.fw.dyn_buckets: 256

And 256 is the default value, it can be increased by the power of 2

I read the man

buckets hash-table-size
Specifies the size of the hash table used for storing the various queues. Default value is 64 controlled by the sysctl(8) variable net.inet.ip.dummynet.hash_size, allowed range is 16 to 65536.

net.inet.ip.fw.curr_dyn_buckets: net.inet.ip.fw.dyn_buckets. The current number of buckets in the hash table for dynamic rules (readonly).

What is a dynamic bucket, why dynamic ?
Let's say I log in ssh in the server what will happen from a bucket point of view ?

Does someone know where I can find exact informations that explain this topic in a "dummy" style because I'm not able to understand the man. Or explain it.

Thank you

 

[Crest]

IIRC ipfw uses a simple hash table to implement dynamic state lookup with linear lists per hash bucket and net.inet.ip.fw.dyn_buckets represents the number of hash buckets containing at least one entry.