Nikita Konyshev
@nikitakonyshev
VoIP / Telephony Engineer at Voxys who built and hardened a Kamailio SBC for live carrier and client traffic.
ThailandWhat I'm looking for
At Voxys, I built and maintain a Kamailio-based SBC in front of FreeSWITCH media servers, using rtpengine for media relay and dispatcher-based carrier failover. I also diagnose certificate-verification failures that block trunk registration.
At Voxys, I audited Kamailio routing logic against five threat categories and patched a logical-operator bug that opened a SQL-injection path in trunk validation, as well as a bug that disabled a WebSocket UA allowlist. I provisioned and maintained SIP gateways and wrote SIPp scenarios to validate trunk registration and call flows.
At Gliptika, I kept Asterisk and FreeSWITCH platforms available under production load, adding defenses with iptables, CrowdSec, and Fail2ban. I automated server provisioning and configuration management with Ansible and Python, and investigated call-quality issues using SIP/RTP traces.
Earlier, at Finenumbers, I supported clients, configured Asterisk servers, and managed Virtual PBX and RTU systems. I also worked with VoIP gateways and diagnosed call-quality and connectivity issues using packet-capture tools.
Experience
Work history, roles, and key accomplishments
VoIP / Telephony Engineer
Voxys
Feb 2026 - Present (9 months)
Built and maintained a Kamailio-based SBC with TLS/mTLS trunks and rtpengine media relay in front of FreeSWITCH media servers. Led a security audit of routing logic, patched a SQL-injection path and a WebSocket allowlist bug, and provisioned 20+ SIP gateways.
VoIP Engineer
Gliptika
Aug 2021 - Feb 2026 (4 years 6 months)
Maintained high availability of Asterisk/FreeSWITCH platforms and layered defenses with iptables, CrowdSec, and Fail2ban. Automated provisioning with Ansible and Python, and root-caused call-quality issues from raw SIP/RTP traces.
VoIP Support Engineer
Finenumbers
Jun 2015 - Jun 2021 (6 years)
Provided advanced technical support for VoIP equipment and softphones, configured and administered Asterisk servers, and analyzed VoIP traffic with tcpdump, tshark, and Wireshark. Managed Virtual PBX and RTU systems and worked with VoIP gateways from Eltex, Grandstream, and Addpack.
Assistant System Administrator
VentKompleks
Oct 2012 - Apr 2014 (1 year 6 months)
Administered user workstations, provided technical support, and assembled and repaired PCs. Managed user accounts with Active Directory and eDirectory, and configured Wi-Fi networks.
Education
Degrees, certifications, and relevant coursework
Udemy
Learn SIP through Kamailio, SIP
Completed the 'Learn SIP through Kamailio' course on Udemy.
Availability
Location
ThailandAuthorized to work in
Salary expectations
Job categories
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