# RTMP Handshake failed: server responded with unexpected version byte 0x03

- **ID:** `communication/rtmp-handshake-failed`
- **Domain:** communication
- **Category:** protocol_error
- **Error Code:** `0x03`
- **Verification:** ai_generated
- **Fix Rate:** 79%

## Root Cause

RTMP client and server fail to negotiate handshake because the server expects Flash Player version 9+ (byte 0x03) but the client sends an older or malformed version (e.g., 0x00 or 0x01), often due to outdated libraries or firewall manipulation.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| RTMP specification (Adobe) | active | — | — |
| FFmpeg 6.0 | active | — | — |
| OBS Studio 29.1 | active | — | — |
| nginx-rtmp-module 1.2.2 | active | — | — |
| Wowza Streaming Engine 4.8.0 | active | — | — |

## Workarounds

1. **Update the RTMP client library to a version that sends the correct handshake byte (0x03): for FFmpeg, upgrade to 6.0 or later; for OBS, ensure version 29.0+.** (90% success)
   ```
   Update the RTMP client library to a version that sends the correct handshake byte (0x03): for FFmpeg, upgrade to 6.0 or later; for OBS, ensure version 29.0+.
   ```
2. **Override the handshake version on the server side: in nginx-rtmp-module, set 'rtmp_version 3;' in the configuration to force acceptance of older clients (though this may reduce security).** (80% success)
   ```
   Override the handshake version on the server side: in nginx-rtmp-module, set 'rtmp_version 3;' in the configuration to force acceptance of older clients (though this may reduce security).
   ```
3. **Use a proxy to rewrite the handshake: deploy a simple RTMP proxy (e.g., using Node.js 'node-rtmp-server') that intercepts the client's version byte and sends the expected 0x03 to the server.** (75% success)
   ```
   Use a proxy to rewrite the handshake: deploy a simple RTMP proxy (e.g., using Node.js 'node-rtmp-server') that intercepts the client's version byte and sends the expected 0x03 to the server.
   ```

## Dead Ends

- **** — Disabling RTMP authentication (e.g., removing 'rtmp_auth' in nginx) does not affect the handshake version negotiation; the version byte mismatch persists. (80% fail)
- **** — Using a different streaming protocol (e.g., RTSP instead of RTMP) changes the issue but may introduce new compatibility problems with the server. (70% fail)
- **** — Increasing the handshake timeout (e.g., 'rtmp_handshake_timeout 30s') only delays the failure; the version mismatch remains. (85% fail)