It depends. It is not necessary for me to enable stun in Asterisk and other voip devices behind NAT. If you need to , you may try this one stun.xten.com
1. I'm testing it from outside and connect back to my home network
2. I don't have any QNAP and my asterisk is run under ubuntu.
I just figured out my Android SIP client (CSIPSimple) need to enable the stun server in order to hear the sound. Any recommendation for the stun server? Thanks.
Now I have two servers running at the same time,one is QNAP TS-119 NAS Asterisk and the other is Intel ATOM-based D515 Asterisk. I may add another one IP-01 later. If I have time, I may add one more for testing purpose.
问题: 用SPA IP Phone注册可以(例如ext 2001),但是在Asterisk Server看到ext 2001 unreachable
解答:
1) 我的第二台Asterisk server B全用default port 5060,而我利用我的router,做port redirection,从5228 UDP Port转到5060 UDP Port of Asterisk server B IP,于是我可以注册到。
2)但是这个“转动”改动是单向,而不是双向, 所以Asterisk server B能注册,在Asterisk server B想发出UDP packets to IP Phone时,因为router不会把Asterisk server B IP:5060, 往外面转至WAN (IP) Port:5228。
3)在更改Asterisk server B的bindport=5228,和router,用port forwarding,WAN的5228,转到Asterisk server IP的5228,就可以。这个转向是双向的。