Hello. I'm Fred Posner
For more than 20 years, I've helped support, design, deploy, and troubleshoot SIP/Telephony systems using Open Source VoIP software.
Fred's primary role is a VoIP Consultant, specializing in Open Source software including Kamailio (formerly OpenSER), Asterisk, and FreeSWITCH
For more than 20 years, Fred has provided SIP/VoIP Engineer consultation services including architecture, design, support, troubleshooting, and more to enterprises, businesses, and carriers.
Contact Fred
Open Source VoIP Consulting
Fred has spent more then 20 years working with open source RTC software. From Kamailio/OpenSER to FreeSWITCH, SIP to RTP, Fred can help your business with design, implementation, scaling, support, and troubleshooting.

Kamailio
Kamailio expert, speaker, and consultant. Proudly working with Kamailio/OpenSER since 2005.
Kamailio Consultant
APIBAN
Fred launched APIBAN as a free service to help protect SIP servers from unwanted SIP traffic.
APIBAN
FreeSWITCH
FreeSWITCH consulting since 2007. A great cross-platform telephony platform / PBX.
FreeSWITCH Consultant
Asterisk
Asterisk consulting/support since 2002. Another telephony platform / PBX.
Asterisk ConsultantHave SIP. Will Travel.
Community Involvement
Fred loves the open source VoIP community and was honored to receive a 2019 SimCon Award (Pre-Posthumous Legend) recognizing his support and contribution.
Fred enjoys evangelizing open source telecom and has spoken at Kamailio World, Astricon, ITEXPO, Cluecon, Asterisk World, and more.
On-Site Assistance
Whiteboardings sessions, training, and projects sometimes need that in person touch. Fred has travelled throughout the world to assist his clients.
Daily and weekly consulting rates are available for on-site work.
Testimonials
Fred utterly embodies the definition of 'reliability' and 'quality'.
Fred should be your go to guy.
A tireless and enthusiastic advocate on behalf of the Kamailio project and, more broadly, in the service of the open-source VoIP ecosystem.
Fred has a very strong work ethic and is a great problem solver.
Fred's problem solving skills have a razor precision that borders on freakish.
His tenacity for troubleshooting and work ethic stand as an example to others. Fred is basically the A-Team in a person.
Selected Video
Open Source Software Myths
Presentation from Kamailio World 2018 in which Fred discusses common myths regarding Open Source software.