If you need a simple RTMP server that can do RTMP live, VOD stream (from flv files), or if you need a simple server to just do some random testing on rtmp streams.
You can just do it with rtmplite. Its there in github if you wanna check it out. But if you want to give it a try as i did, just go ahead and download: http://projects.vvek.in/rtmplite-master.zip
Its a simple RTMP implementation in python. So it would run smooth both on linux and windows. Once you download, just untar it and you can start the server by
python rtmp.py -d ( for debug mode )
Once you have this running on a server say localhost for now. Just go ahead and open https://www.wowza.com/resources/3.6.0/examples/VideoChat/FlashRTMPPlayer/player.html
Click connect and then click allow to allow cam access, then click publish, you are nowstreaming live! and you can access stream at rtmp://localhost/videochat/testing in any rtmp player. You can set it up on a cloud server and you can easily send your stream across other players privately!
The server can stream rtmp vod just fine too, just place flv files in the directory or sub directory where rtmp.py is running and access it as rtmp://localhost/[path to filename.flv]