Timeout dead connections

[Mattias Walström]

Hi!
I still have problems, this is my output from 'who':
admin           pts/0           02:50   Apr  5 07:24:09  x.x.x.x
admin           pts/1           00:00   Apr  5 09:39:05  y.y.y.y

current time:
Fri Apr  5 10:18:27 CEST 2013

shouldn't the first session be timed out? It has not just been idle for 2 h 50 min,
the computer is not there any more. So in my opinion, dropbear should have forgotten the
connection.

Mattias

On 2013-04-01 17:01, Matt Johnston wrote:
> Hi,
>
> The attached attached patch against 2013.56 should fix it, or
> https://secure.ucc.asn.au/hg/dropbear/rev/70811267715c
>
> Dropbear wasn't running cleanup handlers when it exited due
> to the TCP connection being closed.
>
> Matt
>
> On Thu, Mar 28, 2013 at 07:24:55PM +0800, Matt Johnston wrote:
>> I think that -K on the server should be enough. On the
>> server can you run "tcpdump -i eth0 -w cap1.cap port 22",
>> get a ssh session going, pull out the cable, wait 10
>> minutes, then send me the capture?
>>
>> Could you also check that the Dropbear process for the
>> connection is still running after the connection should have
>> been finished. It's possible that the process is exiting but
>> the session cleanup code isn't working correctly. The whole
>> debug log might give me an idea what's going on.
>>
>> Cheers,
>> Matt
>>
>> On Thu, Mar 28, 2013 at 09:56:02AM +0100, Mattias Walström wrote:
>>> Thanks for your responses, all your suggestions imply that you should do something
>>> in the client (set keepalive on client end), but shouldn't the server itself be able to
>>> decide if a client is dead (can't OpenSSH do this?).
>>>
>>> If I do the -K 15 -I 20 on the server end only, this will close the connection when
>>> the OpenSSH client has not sent any characters in 20s. I expected the keepalive to be
>>> two way, that the server got responses on these packages as well, is that not the case?
>>>
>>> Regards
>>>   Mattias
>>
>>>>> On Wed, Mar 27, 2013 at 11:24 AM, Mattias Walström <
>>>>> mattias.walstrom at westermo.se> wrote:
>>>>>
>>>>>> Hi!
>>>>>> I am running dropbear 2013.56, connecting to the server with a PC but
>>>>>> not performing a clean close (I pulled my ethernet cable), this caused
>>>>>> dropbear to never drop its connection.
>>>>>>
>>>>>> Looking at the utmp entries, I could see that the connection never got
>>>>>> dropped,
>>>>>> the utmp entries was kept forever, and running with debug indicates that
>>>>>> also.
>>>>>>   Tried to use -K to send keepalive, but it just keeps sending keepalives
>>>>>> to the peer,
>>>>>> even it is no longer there, and not possible to reach. Shouldn't
>>>>>> the connection be dropped if the keepalive does not reach its destination?
>>>>>>
>>>>>> I know there is the -I option, but that does not really do what I want,
>>>>>> I want the connection to be tear down when the peer is unreachable, not
>>>>>> when the user has been idle for a while.
>>>>>>
>>>>>> Regards
>>>>>>   Mattias
>>>>>>
>>>