Real Time Messaging Protocol (RTMP) was initially a proprietary protocol developed by Macromedia for streaming audio, video and data over the Internet, between a Flash player and a server. Macromedia is now owned by Adobe, which has released an incomplete version of the specification of the protocol for public use.
The RTMP protocol has multiple variations:
- The “plain” protocol which works on top of and uses TCP port number 1935 by default.
- RTMPS which is RTMP over an TLS/SSL connection.
- RTMPE which is RTMP encrypted using Adobe’s own security mechanism. While the details of the implementation are proprietary, the mechanism uses industry standard cryptography primitives.
- RTMPT which is encapsulated within HTTP requests to traverse firewalls. RTMPT is frequently found utilizing cleartext requests on TCP ports 80 and 443 to bypass most corporate traffic filtering. The encapsulated session may carry plain RTMP, RTMPS, or RTMPE packets within.
While the primary motivation for RTMP was to be a protocol for playing Flash video, it is also used in some other applications, such as the Adobe LiveCycle Data Services ES.