SIP · VoIP · Open Source
Telephony systems that work.
For more than 20 years, Fred Posner has helped support, design, deploy, and troubleshoot SIP/Telephony systems using Open Source VoIP software.
What I do
Open Source VoIP consulting.
Experience
20+ years of real-world VoIP engineering.
Fred specializes in Kamailio (formerly OpenSER), Asterisk, FreeSWITCH, SIP, and RTP. Clients use his services for architecture, design, implementation, scaling, support, troubleshooting, and more.
Core belief
Your phone system must increase productivity.
If your current solution forces you to work within boundaries, it may be time to rethink the architecture.
Community
Open source, in the real world.
APIBAN
Fred founded APIBAN in 2020, a free service designed to help prevent unwanted SIP/HTTP traffic.
Visit APIBANSpeaking & community
Fred has participated in and spoken at Kamailio World, Astricon, ITEXPO, ClueCon, Asterisk World, and other VoIP community events.
What others say
Trusted when it matters.
“Fred utterly embodies the definition of ‘reliability’ and ‘quality’.”
“Fred's problem solving skills have a razor precision that borders on freakish.”
“A tireless and enthusiastic advocate on behalf of the Kamailio project and, more broadly, in the service of the open-source VoIP ecosystem.”
Need a hand?
Have SIP. Will Travel.
Whiteboarding, training, projects, and difficult problems sometimes need an experienced engineer in the room.
Get in touch