Use of ClientAliveInterval and ClientAliveCountMax to terminate sftp

shyam

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Nov 2, 2006, 11:11:32 AM11/2/06

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Does ClientAliveInterval and ClientAliveCountMax hold good for
terminating sftp session in case of no dataflow in a SSH channel?

What I am looking for is a mechanism by which I can terminate a sftp
session, if there is no data transfer to the server ?

I tried by setting ClientAliveInterval and ClientAliveCountMax to some
small values and disconnecting network cables right after the
connecting establishment. But the sftp does not terminate for a long
long time.

Is there a way to cut short this time.

I am using Openssh 3.6 on RH Linux AS 3.0 kernel 2.4

thanks

Per Hedeland

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Nov 2, 2006, 4:37:09 PM11/2/06

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In article <1162483891.7...@e3g2000cwe.googlegroups.com>

"shyam" <shyam...@gmail.com> writes:
>Does ClientAliveInterval and ClientAliveCountMax hold good for
>terminating sftp session in case of no dataflow in a SSH channel?

Yes.

>What I am looking for is a mechanism by which I can terminate a sftp
>session, if there is no data transfer to the server ?
>
>I tried by setting ClientAliveInterval and ClientAliveCountMax to some
>small values and disconnecting network cables right after the
>connecting establishment. But the sftp does not terminate for a long
>long time.

The ClientAlive mechanism is a server-side thing - the server sends
messages and expects responses, if it doesn't get them it will terminate
the session. But of course, if you have disconnected the cable, there's
no way the sftp client program can notice this - it's timeout will be
entirely controlled by the TCP parameters on the client host. The
defaults for those vary by OS and they may or may not be settable,
though generally if there is no attempt to send data the timeout is
infinite.

If you want a mechanism within OpenSSH to allow the client to notice
loss of connectivity to the server, you should thus look at the
ServerAlive* settings on the client side...

--Per Hedeland
p...@hedeland.org

shyam

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Nov 2, 2006, 9:43:40 PM11/2/06

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I think ServerAlive setting is now available in openssh3.6
It Might be there in commercial ssh packages , I am not sure
Is there any other way?

> --Per Hedeland
> p...@hedeland.org

shyam

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Nov 3, 2006, 10:23:45 AM11/3/06

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I upgraded to openssh4.3 version from www.openssh.org

With it using ServerAliveINterval & ServerAliveCountMax still dosnt
yeild the desired results I wanted

Any help will be appreciated

thanks

Darren Tucker

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Nov 26, 2006, 7:56:16 AM11/26/06

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On 2006-11-02, shyam <shyam...@gmail.com> wrote:
> Does ClientAliveInterval and ClientAliveCountMax hold good for
> terminating sftp session in case of no dataflow in a SSH channel?
>
> What I am looking for is a mechanism by which I can terminate a sftp
> session, if there is no data transfer to the server ?

No, what those do is send a packet to the client if they have seen one for
a while, but if the client is still running then it will reply and reset
the timer without any interaction from the user.

Basically they help if the client crashes, is killed, rebooted or
drops off the net, but not if the client is simply idle but otherwise
ok.

--
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4 37C9 C982 80C7 8FF4 FA69
Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.