hi sir, i am a senior voip developper with 5 years of experience , i build many CRMS and i worked on VOIP wholesale provider so my missions is installing Dialers and asterisk , freepbx , a2billing and adminstrate Linux servers so i know very much thoses things also fail2ban for the security and iptables so it's the basics on our work
i developped also into a2billing an SMS gatways integration and i administrate it
we can talk any time , this my skype : mrdevelopper
Best regards