[X2Go-User] x2go server closes the inactive connection and not possible to connect again

Pongrácz István pongracz.istvan at gmail.com
Tue Mar 6 19:09:45 CET 2018


Hi,

I use x2go successfully for several years and I very like it, thank
you!

I have a problem with the latest x2go (http://ppa.launchpad.net/x2go/st
able/ubuntu xenial main).
I can login without problem to the server, working as expected, but
when I do not work on the x2go session (inactive or idle), the server
closes the connection and it is not possible to connect again. 
Before the upgrade I had open sessions for days.

Any idea? Below the technical details.

The client debug shows (short version): 
x2go-DEBUG-../src/sshmasterconnection.cpp:2089> Forwarding parameters:
from remote ("localhost":49454) to local ("localhost":49788)
x2go-DEBUG-../src/sshmasterconnection.cpp:2126> Temporary session port
after config file parse: 49454
x2go-DEBUG-../src/sshmasterconnection.cpp:2130> Temporary session host
after config file parse: localhost
x2go-DEBUG-../src/sshmasterconnection.cpp:2160> New channel forwarded.
x2go-DEBUG-../src/sshmasterconnection.cpp:2320> "ssh_channel_write
failed": "Remote channel is closed"
x2go-DEBUG-../src/sshprocess.cpp:472> I/O error: "ssh_channel_write
failed."" - Remote channel is closed" (2).
x2go-DEBUG-../src/sshmasterconnection.cpp:2363> EOF sent.
x2go-DEBUG-../src/sshmasterconnection.cpp:2367> Channel closed.
x2go-DEBUG-../src/onmainwindow.cpp:6459> Proxy wrote on stderr: "Loop:
PANIC! The remote NX proxy closed the connection.
Error: The remote NX proxy closed the connection.
"
x2go-DEBUG-../src/onmainwindow.cpp:6459> Proxy wrote on stderr: "Loop:
PANIC! Failure negotiating the session in stage '7'.
Error: Failure negotiating the session in stage '7'.
Loop: PANIC! Wrong version or invalid session authentication cookie.
Error: Wrong version or invalid session authentication cookie.

So, on the server side the port 49454 did not exist and even on the
server I can see the session running (with ps ax), it is not possible
to connect (The remote NX proxy closed the connection....))

I did not find fresh or relevant information on the net, I spent about
2 days to figure out, but without success (purge, reinstall, xsession
removing etc. - all done, without results)

On the server, the sshd log contains this relevant information (it is
the pair of the client debug log above):
Mar  5 19:45:11 localhost sshd[19999]: Accepted publickey for xxxx from
YYYYY.98 port 43002 ssh2: RSA SHA256:notrelevant
Mar  5 19:45:11 localhost sshd[19999]: pam_unix(sshd:session): session
opened for user username by (uid=0)
Mar  5 19:45:11 localhost systemd-logind[787]: New session 9 of user
username.
Mar  5 19:45:22 localhost su[20438]: Successful su for username by root
Mar  5 19:45:22 localhost su[20438]: + ??? root:username
Mar  5 19:45:22 localhost su[20438]: pam_unix(su:session): session
opened for user username by (uid=0)
Mar  5 19:45:22 localhost systemd-logind[787]: New session c1 of user
username.
Mar  5 19:45:22 localhost su[20438]: pam_unix(su:session): session
closed for user username
Mar  5 19:45:22 localhost su[20492]: Successful su for username by root
Mar  5 19:45:22 localhost systemd-logind[787]: Removed session c1.
Mar  5 19:45:22 localhost su[20492]: + ??? root:username
Mar  5 19:45:22 localhost su[20492]: pam_unix(su:session): session
opened for user username by (uid=0)
Mar  5 19:45:22 localhost systemd-logind[787]: New session c2 of user
username.
Mar  5 19:45:24 localhost su[20492]: pam_unix(su:session): session
closed for user username
Mar  5 19:45:24 localhost systemd-logind[787]: Removed session c2.
Mar  5 19:45:25 localhost sshd[3615]: pam_unix(sshd:session): session
closed for user username
Mar  5 19:45:29 localhost sshd[20011]: error: connect_to localhost port
49454: failed.
Mar  5 19:45:29 localhost sshd[20011]: channel_by_id: 0: bad id:
channel free
Mar  5 19:45:29 localhost sshd[20011]: Disconnecting: Received ieof for
nonexistent channel 0.
Mar  5 19:45:29 localhost sshd[19999]: pam_unix(sshd:session): session
closed for user username
Mar  5 19:45:29 localhost systemd-logind[787]: Removed session 9.

The x2go server log from the syslog:
Here is the session opened first time, successfully, you can see the
agent port (49454):
Mar  5 18:31:11 localhost /usr/bin/x2gostartagent: creating new
session: username-50-1520271069_stDMATE_dp24
2a3a4f78ebac6c1318558ebfebbffff1 3799 YYYY.98 49454 49455 49456 -1 -1

In the syslog I did not find any related information about nxagent
closing, but only the unsuccessful reconnect after 1 hour and 14
minutes. First reconnect, I was able to see the session selector window
and I saw the session as running state, but I had only Suspend and
Terminate buttons active. I pushed the suspend and resume, problem
occurred.

Here are the packages on the server:
ii  cups-x2go                                    3.0.1.3-
1                                    all          Virtual X2Go printer
for CUPS
ii  libx2go-log-perl                             4.1.0.0-
0~1517~ubuntu16.04.1                 all          Perl X2Go::Log
package
ii  libx2go-server-db-perl                       4.1.0.0-
0~1517~ubuntu16.04.1                 i386         Perl X2Go::Server:DB
package
ii  libx2go-server-perl                          4.1.0.0-
0~1517~ubuntu16.04.1                 all          Perl X2Go::Server
package
rc  x2goagent                                    2:3.5.0.33-
0~710~ubuntu16.04.1               all          X2Go agent
rc  x2godesktopsharing                           3.1.1.4-
0~186~ubuntu16.04.1                  i386         Share X11 desktops
with other users via X2Go
ii  x2gomatebindings                             0.0.1.5-
0~203~ubuntu16.04.1                  i386         X2Go MATE bindings
and MIME types
ii  x2goserver                                   4.1.0.0-
0~1517~ubuntu16.04.1                 i386         X2Go server daemon
scripts
ii  x2goserver-common                            4.1.0.0-
0~1517~ubuntu16.04.1                 i386         X2Go Server (common
files)
ii  x2goserver-extensions                        4.1.0.0-
0~1517~ubuntu16.04.1                 all          X2Go Server
(extension support)
ii  x2goserver-printing                          4.1.0.0-
0~1517~ubuntu16.04.1                 all          X2Go server (printing
support)
ii  x2goserver-x2goagent                         4.1.0.0-
0~1517~ubuntu16.04.1                 all          X2Go Server's X2Go
Agent
rc  x2goserver-xsession                          4.1.0.0-
0~1517~ubuntu16.04.1                 all          X2Go Server (Xsession
runner)

Here are the packages on the client:
ii  cups-
x2go                                                   3.0.1.3-
1                                        all          Virtual X2Go
printer for CUPS
rc  x2goagent                                                   2:3.5.0
.33-0~710~ubuntu16.04.1                   all          X2Go agent
ii  x2goclient                                                  4.1.1.1
-0~1719~ubuntu16.04.1                     amd64        X2Go Client
application (Qt4)
rc  x2gomatebindings                                            0.0.1.5
-0~203~ubuntu16.04.1                      amd64        X2Go MATE
bindings and MIME types
rc  x2goserver                                                  4.0.1.2
2-0~1197~ubuntu16.04.1                    amd64        X2Go server
daemon scripts
rc  x2goserver-
printing                                         4.0.1.22-
0~1197~ubuntu16.04.1                    all          X2Go server daemon
scripts (printing)
rc  x2goserver-
xsession                                         4.0.1.22-
0~1197~ubuntu16.04.1                    all          X2Go server daemon
scripts (Xsession runner)
ii  x2gousbmount                                                1.1.0.2
-0~469~ubuntu16.04.1                      all          clientside usb
mass-storage device mounting
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