Direct answer
UDP 3702 is associated with WS-Discovery, but the camera’s ONVIF device service can listen on a different HTTP or HTTPS port chosen by the vendor. Use discovery to learn the service address, then connect to that returned endpoint.
Why this happens
Calling every ONVIF operation on port 3702 fails because discovery is not the same as the device-management or media service. Vendor FAQs may also name a model-specific ONVIF service port.
Discovery only locates a device service; media profiles, credentials and routing still require their own checks.
A controlled test
Capture the discovery response and read the xaddr rather than guessing a service port.
Change one variable at a time. Keep the camera model, firmware, endpoint and account recorded; then test network reachability, protocol response, media transport and decoding as separate layers.
Use a dedicated view-only account and a trusted local diagnostic tool. Redact credentials, private addresses and identifying data before sharing output.
Diagnostic sequence
| Check | Action | Evidence of progress |
|---|---|---|
| Probe | Run discovery on the local camera network. | A response identifies the device and xaddr. |
| Address | Parse the xaddr scheme, host, port and path. | The service endpoint is explicit. |
| Call | Authenticate to the returned device service. | Capabilities and profiles are available. |
| Stream | Request and test the media URI separately. | RTSP playback is verified on its own port. |
Evidence to keep
Document three fields separately: discovery transport, ONVIF service endpoint and RTSP stream endpoint.
Boundary and safety note
Model-specific service ports are not universal defaults; confirm them in official documentation or the discovery response.
For remote viewing, use a managed VPN instead of exposing RTSP or camera administration ports directly to the public internet.
SmartRTSP
SmartRTSP is a camera-focused RTSP and ONVIF viewer for Apple devices, Windows and Android. It fits direct viewing, discovery and multi-camera checks; keep a dedicated NVR or VMS when continuous recording, evidence export or centralized enterprise controls are required.
Frequently asked questions
Is 3702 the ONVIF video port?
No. It is used for WS-Discovery; video normally uses a separate RTSP or HTTPS media path.
Why does my camera use another ONVIF port?
The vendor can expose the ONVIF HTTP or HTTPS service on a model-specific port.
Should I scan many ports to find ONVIF?
Prefer local discovery, current vendor documentation or the camera configuration instead of broad scanning.
Primary references
- ONVIF — Profiles and conformance overview
- ONVIF — Profile T for advanced video streaming
- IETF RFC 7826 — Real-Time Streaming Protocol 2.0
Related SmartRTSP guide
Open related guideSeparate WS-Discovery traffic from the HTTP or HTTPS endpoint used for ONVIF device and media calls.