TIME_WAIT issue

[japita-se]

We use authentication for subscribe and a Mysql backend to search for credentials.
The broker is behind a router which forwards all packets to a particular port on the broker.
For unhautenthicated users we experience a lot of TIME_WAIT stale connections which suck the CPU and fill the memory up to 8Gb. The number of TIME_WAIT connections is around 2000.
Any hint? I suppose that