At this point the lab environment looks like the following image:

Make sure that any ping connectivity test between the Ubuntu desktops should be successful.

Open Linphone in both Ubuntu desktops, click on the right top bar menu and select Preferences.

Under SIP accounts tab remove any Proxy accounts, to make things clear, lets use Alice and Bob as the usernames including a suffix indicating if they are related to the Internal or External Ubuntu device.

This is the configuration for the external part:

And internal part:

All other settings will be the same for both Ubuntu desktops:

Enable only PCMU and PCMA audio codecs:

Settings for Video:

Calls and Chat:

Network:

Leave User Interface and Advanced configuration with the default settings.

As mentioned before, to test this environment the Home Network will be used (IP addressing 192.168.1.x), type Bob address in Alice softphone:

Answer the call in Bob application, in this case Wireshark was also opened to validate RTP transmission. This test help us to validate Linphone works correctly using a direct connection between Ubuntu desktops.

Different information can be gotten from Wireshark but we will go deeper in a future entry.