Since the issue #1047 got fixed RCon works again and everything seems normal. However for me it leaves tons of "CLOSE_WAIT" connections behind whenever an rcon client disconnects (this here is just a few RCON queries done from munin).

After a certain time this causes the Minecraft server's performance to heavily degrade (they never get closed, only fix is a full server restart).

The Munin plugins I used (PHP based) can be found here: https://github.com/LizardNet/munin-plugins-minecraft
(However any other usage of the RCON protocol I have tried has also caused this)

No matter if the RCON authentication succeeds or fails, it just keeps in CLOSE_WAIT state and never vanishes which causes a considerable amount of lag / other problems once they have accumulated beyond a certain level

MC munin-plugins-minecraft # netstat -nap | grep ':401'
tcp 0 0 0.0.0.0:40130 0.0.0.0:* LISTEN 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60485 CLOSE_WAIT 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60488 CLOSE_WAIT 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60504 CLOSE_WAIT 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60505 CLOSE_WAIT 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60486 CLOSE_WAIT 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60501 CLOSE_WAIT 23911/java
tcp 0 0 10.88.1.3:40130 10.88.1.3:45726 CLOSE_WAIT 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60489 CLOSE_WAIT 23911/java
tcp 0 0 10.88.1.3:40130 10.88.1.3:45728 CLOSE_WAIT 23911/java
tcp 0 0 10.88.1.3:40130 10.88.1.3:45729 CLOSE_WAIT 23911/java
tcp 0 0 127.0.0.1:40130 127.0.0.1:60502 CLOSE_WAIT 23911/java