Short description: I want to use Zoiper softphone on my desktop computer to make outgoing calls (That's it).
I have a SIP currently working account, for example: ( user: 1234, domain: mydomain.co ,pass: qwerty123456) . I am able to make calls using zoIPer android app (USING a data package through 3G/4G network on my celphone with Android5 OS) and everything works fine. But, when I try to use Zoiper through WiFi or LAN(No matter if it is with the same celhpone or with my laptop) ( that is, connected to internet via modem/Router CISCO DPC3825 or if I use the celphone as wiFi hotspot) the call connection is stablised, but there is not incoming audio ( I mean, If I call you, you would be able to hear my voice (outgoing packages ) but I will NOT be able to hear you (zero incoming packages)).
Note0: During the call I opened up the option that says "statistics " and it shows just outgoing packages but Zero (not) incoming (received) packages.
Note1: I had been looking information about "zoIPer ONE WAY AUDIO" and I had found that when I am connected to a modem I need to check:
* If the modem blocks SIP using ALG- onSIP. ( I was checking the modem/router CISCO DPC3825 manual and also I logged in into that modem/router and I was not able to find that option available (it seems it does not exist)).
* If the modem/router firewall is blocking ZoIPer ports ( in the modem, I disabled firewall for IPV4 ,IPV6 and there is a message tha says " No ports restricted").
* If there is port forwarding incorrectly done (in the modem, port filtering is disable, not port forwarding enabled, not port triggering enabled).
* Check if it is possible to setup VPN passthrough or set up your VPN to overpass NAT ( I dont know how to do it).
I already checked previous advises and it seems, so far, none works for me or, I did not followed them properly.
Note 2: At this point I really do not know what else shoud I check. I already checked the CODECs used and noticed (when using 3g/4G networkd the GSM codec works perfect but not when using WiFi). To address the NAT communication I activated the option STUN server on zoIPer (desktop and android app) but still the same issue ( call connections are stablished , people is able to hear my voice, but I am unable to hear them).
Note 3: I don't know if I need to set up my modem/router in such a way that it may not interfere with ZoIPer softphone and how to do it.
Thank you very much in advance for all your help.!!!
Note 4: This is my laptop description:
Reference: Asus R401VM (Laptop)
OS: Linux Ubuntu 16.04 (64 bits)
Zoiper used: I downloaded and installed Zoiper5, free version, and installed the .deb package (Note I already check that all libraries and dependencies where satisfied).