iptables command and parallel processes

Hello,

I want to ask one question about parallel processes and iptables command usage.

What I know about iptables command that it reads tables from kernel to userspace, make needed changes and write whole data back to kernel.

I think that following situation is possible: process "aaa" calls iptables command, iptables (child of "aaa") get data from kernel, at this moment process "bbb" calls iptables, iptables (bbb) get data from kernel, iptables (aaa) make changes, iptables (bbb) make changes, iptables (aaa) write data back to kernel, iptables (bbb) write data to kernel - and we _lost_ result of iptables (aaa).

If above situation impossible - which method is used to prevent it?

If above situation possible - which metod I can use to prevent it?

Best regards,
 Igor                          mailto:[email protected]