1. Create a new trunk in Skip2PBX:

Open your Skip2PBX web interface and go in Channels > SIP > SIP trunks and create a new trunk:

Authentication mode	Username and password
Link mode	Single user
Username	ekiga
Password	ekiga
Auth username	ekiga
DTMF Mode	INFO

2. Create a new account in your Ekiga:

Go to Modify > Prefrences > Protocols > SIP Settings... and fill in the following values:

Outbound proxy	Your Skip2PBX IP
Forwarding URI	sip:xxx.xxx.xxx.xxx	(Replace with your Skip2PBX IP)

Go to Modify > Account then go to Account > Add SIP account and fill in the following values:

Name	ekiga
Registrant	Your Skip2PBX IP
Username	ekiga
Authentication logon	ekiga
Password	ekiga