Is there a "sync" for iptables?

[Renee Darby <reneedarby@xxxxxxxxxxxxx>]

How does the iptables interface work?   It looks like the user command 
sends a message in to the kernel which responds immediately,   the 
kernel appears to queue that command up and not actually commit the 
firewall until it can get a globla lock or somethnig.   Is this how it 
works?   Is there a sync or a way to nknow when the rule was comitted?