Asterisk and NAT

Hope you all will be fine. I want to ask if i am using Nat for my sip users in sip.conf by nat=yes, then is it necessary to set Iptable rules for asterisk? If yes then can please any one tell me how can i check that, what rules for asterisk i have in my Iptables and if the rules for asterisk are not set then how can i set the rules.I am running centos 4.7 with asterisk

Thank you.

I don’t see why you would need to set the iptable rules for your Asterisk unless you want to allow/disallow
access to certain ports on it. If your Asterisk is NAted just make sure that your Internet gateway redirects the
correct SIP UDP ports to your Asterisk (e.g. 5060 + 10000-20000).