VoIP Security Audit
Exposed SIP attracts scanning, brute-force and toll fraud. Zypager reviews your exposure, authentication, routing restrictions and transport security and gives you a prioritised, written set of fixes.
Problems solved
- SIP ports exposed to the internet
- Weak or shared authentication
- No rate limiting (fail2ban alone is not enough)
- Unrestricted international / premium routes
- No TLS/SRTP; no capture or monitoring
How Zypager helps
- Review exposure and trust boundaries
- Harden authentication and rate limiting
- Restrict international / premium routing
- Add TLS/SRTP and capture/monitoring
Technical areas covered
Typical deliverables
- Severity-graded findings report
- Prioritised hardening steps
- Monitoring & response recommendations
Frequently asked questions
Yes. One-way and no-audio problems are usually in the RTP media path or NAT/SDP handling rather than the signalling. With a SIP trace and the SDP from each leg, the media direction can be followed to the point where it stops.
Yes — Asterisk, FreeSWITCH, Kamailio, OpenSIPS and RTPengine. Many real systems combine them (edge proxy, media relay and application logic), and problems often live at the boundaries between them.
WebRTC-related work may be reviewed separately where it is directly connected to Asterisk, Kamailio, RTPengine or SIP troubleshooting, but it is not currently offered as a standard fixed-price service.
Reading traces is central to how Zypager works. A clear pcap, sngrep or Homer export, plus call details, is often enough to identify the failing transaction without live access.
Yes, on an hourly basis for urgent incidents — failed inbound/outbound calls, RTP/no-audio and carrier problems. Final scope and availability depend on access and complexity.
Related services
SIP Capture / Homer
See every call. Search by Call-ID. Escalate with evidence.
Kamailio Consulting
SIP edge routing, registrar and dispatcher built to scale.
Asterisk + Kamailio + RTPengine Deployment
A full voice stack — edge, media and application — built and documented.
Not sure which service you need?
Send the symptoms and a call example. The right starting point becomes obvious from the trace.