sipmon is a passive monitor for SIP signaling and RTP media quality that runs as a standalone Rust executable on Linux without a running PBX. It accepts live interface captures, pcap and pcapng files, tcpdump streams from stdin, and recorded event logs. It groups calls and transactions by Call-ID and can reassemble SIP-over-TCP traffic. Its media measurements include RFC3550 jitter and loss, RTCP round-trip time, one-way delay estimates, and estimated E-model MOS. More than 20 diagnostic rules cover topics including Contact reachability, Record-Route, SDP/RTP consistency, one-way media, and TURN allocation or refresh. sipmon can learn TURN servers and label client and peer relay legs automatically. A terminal interface includes pages for call details, SIP statistics, streams, event logs, and IP statistics; it also supports JSONL exports and Call-ID queries. Event logs retain analysis summaries and truncated raw SIP messages, but not raw RTP payload. Prebuilt static binaries are available for Linux x86_64 and aarch64, with Cargo installation also documented.
Who it is for
sipmon suits teams monitoring SIP and RTP traffic on Linux, including deployments using a mirrored port or capture box. It is aimed at analysis of captured traffic rather than synthetic call testing.
What is good
- Runs without a PBX dependency.
- Reads live captures, packet files, streams, and event logs.
- Reports jitter, loss, delay estimates, and MOS.
- Offers more than 20 diagnostic rules.
- Raw RTP payload is not stored.
What to know first
- Prebuilt binaries are listed for Linux only.
- Capture can compete with rtpengine for CPU on busy hosts.
- Documented defaults cap memory at 100,000 calls.
Verdict
sipmon provides detailed signaling and media diagnostics through terminal views, queries, and exports. For busy relay hosts, account for capture load and consider the documented filtering or dedicated capture setup.
Compared on VoIP monitoring software
- MOS scoring
- Yes
- Jitter tracking
- Yes
- Packet-loss tracking
- Yes
- Synthetic call tests
- No
