No mic/voice working when registered via public IP on android

Question

Hi,

I can successfully register my zoiper-client on an android-based mobile phone with my dsl-router (fritzbox) which is my call manager.

I use the public IP of the dsl-router for registration (dyndns).

I get all calls and can make calls from the mobile phone. but here's the catch - there is no voice transported from the mobile device, i.e. on my mobile I can hear everything but when I speak nothing arrives at the other client.

Now if I use the private address of the dsl-router for registration of the zoiper-client, voice is working.

I don't have this behavior when I use a different app (CSipsimple for example).

Any suggestions?

cheers

Answer 1

" public IP"  Did you perhaps mean internet routable as opposed to private network IP address?

Ergo not any of these:

10.0.0.0/8 (255.0.0.0)

172.16.0.0/12 (255.240.0.0)

192.168.0.0/16 (255.255.0.0)