Soln for NAT Traversal in SIP using stun server in Asterisk

I am doing a project on NAT Traversal through SIP in IMS network. There are some problems for a NAT traversal in SIP. One of the solution is the STUN and TURN servers. I think that there is some feature about the STUN server in Asterisk. Could i get some ideas like how should I use it and what can be done with it to use in my project?

Ashfaaq Poonawala