WSO2 ESB too many open files

问题

We have a problem in our installation of wso2 esb.

We have only 4 proxy services configured, after one month without problems we started to have the following error:

2013-10-02 09:29:09,366 [-] [PassThroughHTTPSListener]  WARN PassThroughHttpSSLListener System may be unstable: HTTPS ListeningIOReactor encountered a checked exception : Too many open files
java.io.IOException: Too many open files
at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:189)
at org.apache.http.impl.nio.reactor.DefaultListeningIOReactor.processEvent(DefaultListeningIOReactor.java:129)
at org.apache.http.impl.nio.reactor.DefaultListeningIOReactor.processEvents(DefaultListeningIOReactor.java:113)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:313)
at org.apache.synapse.transport.passthru.PassThroughHttpListener$2.run(PassThroughHttpListener.java:180)
at java.lang.Thread.run(Thread.java:738)

If I list the list of files open by java, I will see hundreds of:

java      3906       root  150u     sock                0,7         0t0       9928 can't identify protocol
java      3906       root  151u     sock                0,7         0t0      10004 can't identify protocol

Someone could point me out the cause of this error?

Thank you.