I ran into this problem with every j2ee appserver from old days of iPlanet 6.0 until today. I our case it were always the IIOP connections that brougt the orb down.
Sometimes it was a missing patch in the os or the appserver, but it always needed a change of ulimit. Today we'vre ulimit set up to 65536.
But there seemed to be a kind of bug, because idle connections with no ip's associated are not getting closed. Only after a stop/start of the appserver.
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