+---------------+                +-----------------+
|               |    request    _|_                |
|               |        .---> /   \   224.0.1.187 |
|              _|_      /      \___/ --.   :9999   |
| 192.168.0.1 /   \ ---´         |      \          |
|   :54321    \___/ <---.       _|_     /  rewrite |
|               |        \     /   \ <-´           |
|               |         `--- \___/ 192.168.0.100 |
|               |    response    |         :5683   |
+---------------+                +-----------------+
      Client                           Server