Does Nginx or Nginx Plus can be used as DTLS termination proxy? I tried to do simple proxy something like this

stream {
server {
listen 20001 udp;
proxy_pass 172.17.0.1:20000;
}

server {
listen 1884;
proxy_pass 172.17.0.1:1883;
}
}

It works for TCP but it breaks connection/packets for UDP. I tried on a very simple python proxy and forwarding UDP packets works but with Nginx not. I want to achive something like this: MQTT-SN client -> (DTLS encryption) -> (DTLS termination proxy) -> MQTT-SN Gateway is it possible with Nginx?

There is experimental patch for DTLS protocol. Give it a shot.

http://nginx.org/patches/dtls/README.txt