[Serusers] NAT type detection

Hello, I've been using Asus WL-500G as NAT/Router device for my testing purposes with SER. I implemented MyStun server which is running on the same OS as SER on 192.168.1.50. I also have two IP addresses on the server which are 192.168.1.50-51 for MyStun functionality. When I start MyStun it listens on default ports 3478 an 3479. UA behind the NAT is Xlite so the STUN implemetation of this softphone should be ok. Question 1: Where should I be able to determine/see what type of NAT I'm behind with X-lite? I'm trying to combine NAThelper/RTPproxy with STUN and use STUN if there is no symmetric NAT. Question 2: Could you advice me what tools I should use for debugging functionality of STUN, please? Hopefully, everything is clear. Ladislav