Problems with connections in FIN_WAIT

Richard Whalen

2008-02-20 14:39:06 UTC

According to the code, FIN_WAIT_2 is entered when our FIN is ACKed. I
don't see a FIN in the TCPDUMP below though.

A FIN_WAIT_2 should not persist longer than tcp_maxidle, which has a
default value of tcp_keepcnt (8) * tcp_keepintvl (150) = 1200 ticks.
There are 2 ticks a second, so this would be 600 seconds, or 10 minutes.

Do you believe that the connection that the printer thinks it has with
alpha.1022 is in the TIME_WAIT state? I'm not very familiar with the
stream symbiont code, but it's possible that it is reusing a socket too
quickly.

-----Original Message-----
From: Jeremy Begg [mailto:***@vsm.com.au]
Sent: Tuesday, February 19, 2008 10:15 PM
To: info-***@process.com
Cc: ***@vsm.com.au
Subject: Problems with connections in FIN_WAIT_2 state

Hi,

Process Software MultiNet V5.1 Rev A-X, COMPAQ AlphaServer DS20E 666
MHz,
OpenVMS AXP V8.3

We are having problems with the MultiNet STREAM symbiont and a couple of
printer queues. For reasons unknown, both of these printer queues have
started misbehaving today: they go into the STALLED state and do not
recover.

TCPDUMP shows:

13:54:48.33 alpha.1021 > printer.9100: S 0:0(0) win 6144 <mss
1460,,wscale 0,,,timestamp 30670848:0> (DF)
13:54:48.33 printer.9100 > alpha.1021: R 0:0(0) ack 1 win 0
13:55:02.92 printer.9100 > alpha.1022: . 0:1(1) ack 1 win 7200
13:55:02.92 alpha.1022 > printer.9100: . ack 1 win 7300 (DF)
13:56:07.73 printer.9100 > alpha.1022: . 0:1(1) ack 1 win 7200
13:56:07.73 alpha.1022 > printer.9100: . ack 1 win 7300 (DF)

You'll notice that the printer rejected the connection attempt because
it
believes it already has a connection active on port 1022 (in this case).
I can clear this by powering the printer off and on, but it keeps on
happening.

I notice that MultiNet thinks this connection is in the FIN_WAIT_2
state:

$ pipe mu show/conn=pid/nosym | sear sys$pipe: "1.17"
<kernel> 0 0 192.168.1.2(1022) 192.168.1.17(9100)

$

So I have two questions:
1. Will the FIN_WAIT_2 connection ever be deleted, and when?
2. Is there some way short of rebooting the machine that I can force
MultiNet to delete this connection?

Thanks,

Jeremy Begg

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