[erlang-questions] phantom ports in erlang:ports()

Jesper Louis Andersen jesper.louis.andersen@REDACTED
Fri Nov 16 10:32:13 CET 2012

On Nov 16, 2012, at 7:29 AM, Valentin Micic <valentin@REDACTED> wrote:

> I am wondering if this may be attributed to CLOSE_WAIT/TIME_WAIT states sockets may be in during the connection shutdown?
> By the some token, if the server in question has a higher frequency of short-lived connections,  this may also explain discrepancy between number of file descriptors as reported by lsof and number of active ports reported by emulator.

TIME_WAIT is not a problem. It is just the kernel keeping track of the connection if packets get sent still by the other end. CLOSE_WAIT on the other hand sounds bad. This state should happen when the other end has sent a FIN and started to close down the socket, but the application (i.e., Erlang?) has not closed the socket down yet.

If you have lingering CLOSE_WAITs that are there for a long time it is usually a warning sign that something may be bad.

Jesper Louis Andersen
  Erlang Solutions Ltd., Copenhagen

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