Bug 903186

Same problem here with freenx-server-0.7.3-29.fc18.x86_64.

When attempting connection I receive the error:

NX> 203 NXSSH running with pid: 9815
NX> 285 Enabling check on switch command
NX> 285 Enabling skip of SSH config files
NX> 285 Setting the preferred NX options
NX> 200 Connected to address: 10.x.y.z on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
HELLO NXSERVER - Version 3.2.0-74-SVN OS (GPL, using backend: 3.5.0)
NX> 105 hello NXCLIENT - Version 3.2.0
NX> 134 Accepted protocol: 3.2.0
NX> 105 SET SHELL_MODE SHELL
NX> 105 SET AUTH_MODE PASSWORD
NX> 105 login
NX> 101 User: mpd
NX> 102 Password: 
NX> 103 Welcome to: zbox user: mpd
NX> 105 listsession --user="mpd" --status="suspended,running" --geometry="1680x1818x24+render" --type="unix-application"
NX> 127 Sessions list of user 'mpd' for reconnect:

Display Type             Session ID                       Options  Depth Screen         Status      Session Name
------- ---------------- -------------------------------- -------- ----- -------------- ----------- ------------------------------


NX> 148 Server capacity: not reached for user: mpd
NX> 105 startsession  --rootless="1" --virtualdesktop="0" --application="/usr/bin/quodlibet" --link="lan" --backingstore="1" --encryption="1" --cache="16M" --images="64M" --shmem="1" --shpix="1" --strict="0" --composite="1" --media="0" --session="quodlibet" --type="unix-application" --client="linux" --keyboard="pc102/ca" --screeninfo="1680x1818x24+render" 

Ncat: Connection refused.
NX> 280 Exiting on signal: 15

Same problem here: freenx-server-0.7.3-29.fc18.x86_64 and same symptoms as above, when trying to connect with No Machine NX Client for Windows 3.5.0.9.

In my case, it seems that adding "2>/dev/null" (without quotes) at the end of all $COMMAND_NETCAT lines in /usr/libexec/nx/nxserver fixed the issue.

Additional investigation appears to suggest that the NX Client does not like "Connection refused" appearing anywhere in the received log. This was tested by adding echo "Test: Connection refused" or echo "Connection refused" before the session_add call in server_startrestore_session; it resulted in same symptoms as above. The old netcat silently returned 1 when closed ports were probed, whereas the new one unfortunately prints "Ncat: Connection refused", causing the issue.

By golly, the fix in comment #2 worked for me as well. I must not be getting that error at home (maybe I have some service it checks enabled at home and don't have it enabled at work).

Thanks for the work around!

Nice work Rok Mandeljc. Fix works for me as well.

diff nxserver-orig nxserver
1494c1494
<                         if $COMMAND_NETCAT --send-only "$SERVER_HOST" $PROXY_DISPLAY </dev/null
---
>                         if $COMMAND_NETCAT --send-only "$SERVER_HOST" $PROXY_DISPLAY </dev/null 2>/dev/null
1504c1504
< 			if [ "$(getparam 'samba')" = 1 ] && $COMMAND_NETCAT --send-only "$SERVER_HOST" $SAMBA_DISPLAY </dev/null
---
> 			if [ "$(getparam 'samba')" = 1 ] && $COMMAND_NETCAT --send-only "$SERVER_HOST" $SAMBA_DISPLAY </dev/null 2>/dev/null
1512c1512
< 			if [ "$(getparam 'media')" = 1 ] && $COMMAND_NETCAT --send-only "$SERVER_HOST" $MEDIA_DISPLAY </dev/null
---
> 			if [ "$(getparam 'media')" = 1 ] && $COMMAND_NETCAT --send-only "$SERVER_HOST" $MEDIA_DISPLAY </dev/null 2>/dev/null
1521c1521
< 			if [ "$(getparam 'cups')" = 1 ] && $COMMAND_NETCAT --send-only "$SERVER_HOST" $CUPS_DISPLAY </dev/null
---
> 			if [ "$(getparam 'cups')" = 1 ] && $COMMAND_NETCAT --send-only "$SERVER_HOST" $CUPS_DISPLAY </dev/null 2>/dev/null
1640c1640
< 				$COMMAND_NETCAT $SERVER_HOST $PROXY_DISPLAY
---
> 				$COMMAND_NETCAT $SERVER_HOST $PROXY_DISPLAY 2>/dev/null

Any freenx maintainers looking at this bug might want to glance at bug 903410 as well. I have called it a gtk 3 bug for now, but maybe it is really an NX bug?

Testing with remmina nx on my f-16 freenx-server box which I've patched to use ncat I get a genuine "Ncat: Connection refused" in the remmina log but it doesn't seem to matter; I succeed in logging in every time. Adding fake "Connection refused" echos as mentioned in comment 2 makes no difference either, it is shown in the logs but doesn't break logins. It'll take some time until I have a f-18 freenx-server box to test against.

Maybe the issue is specific to NoMachine NX client, then? Even so, it appears to be caused by increased verbosity of the new ncat.

(In reply to comment #7)
> Maybe the issue is specific to NoMachine NX client, then?

Confirmed that NoMachine nxclient-3.5.0-7 has this issue (FWIW nxplayer-4.0.181-3 apparently doesn't).

BTW I'm leaving out the last hunk of the patch in comment 4 - that particular ncat call is not a "probe" one like the others and if that one fails, things will go south anyway and I don't think it'd be a good thing to hush stderr there.

freenx-server-0.7.3-30.fc18 has been submitted as an update for Fedora 18.
https://admin.fedoraproject.org/updates/freenx-server-0.7.3-30.fc18

Package freenx-server-0.7.3-30.fc18:
* should fix your issue,
* was pushed to the Fedora 18 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing freenx-server-0.7.3-30.fc18'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2013-1477/freenx-server-0.7.3-30.fc18
then log in and leave karma (feedback).

freenx-server-0.7.3-30.fc18 has been pushed to the Fedora 18 stable repository.  If problems still persist, please make note of it in this bug report.