[X2go-dev] remote proxy closed the connection

Gerry Reno greno at verizon.net
Sat Feb 5 02:31:53 CET 2011


On 02/04/2011 06:09 PM, Gerry Reno wrote:
> On 02/04/2011 06:01 PM, Gerry Reno wrote:
>   
>> On 02/04/2011 04:43 PM, Mike Gabriel wrote:
>>   
>>     
>>> Hi Gerry,
>>>
>>> On Fr 04 Feb 2011 22:14:28 CET Gerry Reno wrote:
>>>
>>>     
>>>       
>>>> Has anyone found out how to prevent this "remote proxy closed the
>>>> connection" error from happening when a session becomes detached and a
>>>> user tries to resume the session?
>>>>
>>>> We are seeing this problem quite often and every once in a while you can
>>>> get it to resume but mostly this session is unrecoverable and must be
>>>> manually terminated - which is creating much sysadmin work.
>>>>       
>>>>         
>>> Test the following:
>>>
>>> Whenever this error occurs, restart your X2go server's SSH daemon. My
>>> guess is that you can resume the session once SSH is restarted.
>>>
>>> I have read about weird port forwarding habits of the SSH daemon... I
>>> also meet these problems with PyHoca-GUI.
>>>
>>> Greets,
>>> Mike
>>>
>>>     
>>>       
>> Ok, the plot thickens.
>>
>> I took a look at netstat both prior-to and after we get this error:
>>
>> # normal state
>> # we can successfully resume a session
>>
>>     # netstat -a | grep 300
>>     tcp        0      0 localhost:30008         *:*                    
>>     LISTEN    
>>     tcp        0      0 localhost:30009         *:*                    
>>     LISTEN    
>>     tcp6       0      0 ip6-localhost:30008     [::]:*                 
>>     LISTEN    
>>     tcp6       0      0 ip6-localhost:30009     [::]:*                 
>>     LISTEN    
>>
>>
>> # # after I forced a session to detach
>>
>>     # netstat -a | grep 300
>>     tcp        0      0 localhost:30008         *:*                    
>>     LISTEN    
>>     tcp        0      0 localhost:30009         *:*                    
>>     LISTEN    
>>     tcp        0      0 localhost:33552         localhost:30037        
>>     TIME_WAIT 
>>     tcp6       0      0 ip6-localhost:30008     [::]:*                 
>>     LISTEN    
>>     tcp6       0      0 ip6-localhost:30009     [::]:*                 
>>     LISTEN    
>>
>>
>> # # if we just wait for a while then reattempt to resume the session it
>> succeeds
>>
>>     # netstat -a | grep 300
>>     tcp        0      0 localhost:30008         *:*                    
>>     LISTEN    
>>     tcp        0      0 localhost:30009         *:*                    
>>     LISTEN    
>>     tcp6       0      0 ip6-localhost:30008     [::]:*                 
>>     LISTEN    
>>     tcp6       0      0 ip6-localhost:30009     [::]:*                 
>>     LISTEN    
>>
>>
>> So whatever is causing this TIME_WAIT is what appears to have a role in
>> the error.
>>
>>
>> Regards,
>> Gerry
>>
>>
>>
>>   
>>     
> What's interesting is that it presents the menu and the process is shown
> as "running" so then your "suspend" it and "resume" it and you still get
> the "remote proxy closed the connection" error and NX proxy shows
> "aborting" but it does resume the session.  Very confusing to users but
> at least they get their session back.
>
>
> Regards,
> Gerry
>
>   

The TIME_WAIT occurs on the server because apparently there is no
keep_alive which would make the client responsible for closing the
connection.  I didn't see any TCPKeepAlive=yes in the ssh options which
may be accounting for TIME_WAIT showing up on the server.


Regards,
Gerry





More information about the x2go-dev mailing list