Hi,

I completely self-built the server, the client is downloaded from the website :)

Thanks for the debug hint, will try :)

Cs.

On Sat, Jul 5, 2025 at 7:48 PM Anakien Skywalker <[email protected]> wrote:
>>
>> First @Anakien, i checked a target computer, and there are even no
>> logins happening here, so the communication is not reaching. I have no
>> internal firewalls or so, and the server where Guacamole runs, can
>> reach this computer with ssh command from shell. In addition, ssh from
>> Guacamole does not work towards none of the computers here. (But this
>> was a good idea, anyway, it could be reveal problems, so thx :) )
>
> This is what I thought. The connection is closed before it is actually 
> established. Something is wrong between guacamole client (if you use 
> guacamole client) and guacd. Did you upgrade the client to 1.6.0 as well? You 
> would need to put it in debug mode and provide logs as well. It is a bit more 
> complicated then turn on debug for guacd: 
> https://guacamole.apache.org/doc/gug/configuring-guacamole.html#logging-within-the-web-application
>
>
> сб, 5 июл. 2025 г. в 20:43, Horváth Csaba <[email protected]>:
>>
>> Hi,
>>
>> First @Anakien, i checked a target computer, and there are even no
>> logins happening here, so the communication is not reaching. I have no
>> internal firewalls or so, and the server where Guacamole runs, can
>> reach this computer with ssh command from shell. In addition, ssh from
>> Guacamole does not work towards none of the computers here. (But this
>> was a good idea, anyway, it could be reveal problems, so thx :) )
>>
>> @Nick Couchman : Yes, the UUID appears in this way in the logs. Was
>> strange for me too but not enough... :D
>> Stopping traffic - i have no firewalls on the computers, and SSH
>> itself works. So this can be an issue with guacd, i think. The double
>> free is strange, but i have no signs of something crashing or
>> segfaulting (also suspicious, because such an error cold be
>> related...).
>> Guacd and Guacamole webserver are running on the same computer. All
>> other connection types are working, except SSH.
>>
>> How do i put the client in debug mode?
>> Tomcat log in normal mode during an SSH connection - during this i can
>> see the gray "Connected to Guacamole. Waiting for response" :
>> [2025-07-05 19:33:35] [info] 19:33:35.887 [http-nio-8080-exec-11]
>> DEBUG o.a.g.event.EventLoggingListener - User "user" (authenticated by
>> "default") successfully re-authenticated their existing session from
>> [192.168.1.103, 127.0.0.1]
>> [2025-07-05 19:33:36] [info] 19:33:36.024 [http-nio-8080-exec-19]
>> DEBUG o.a.g.net.InetGuacamoleSocket - Connecting to guacd at
>> localhost:4822.
>> [2025-07-05 19:33:36] [info] 19:33:36.043 [http-nio-8080-exec-19] INFO
>>  o.a.g.tunnel.TunnelRequestService - User "user" connected to
>> connection "T480 SSH".
>> [2025-07-05 19:33:36] [info] 19:33:36.043 [http-nio-8080-exec-19]
>> DEBUG o.a.g.event.EventLoggingListener - Ignoring
>> unknown/unimplemented event type: class
>> org.apache.guacamole.net.event.TunnelConnectEvent
>> [2025-07-05 19:33:36] [info] 19:33:36.043 [http-nio-8080-exec-19] INFO
>>  o.a.g.t.h.RestrictedGuacamoleHTTPTunnelServlet - Using HTTP tunnel
>> (not WebSocket). Performance may be sub-optimal.
>> [2025-07-05 19:33:36] [info] 19:33:36.043 [http-nio-8080-exec-19]
>> DEBUG o.a.g.s.GuacamoleHTTPTunnelServlet - Registered tunnel
>> "a9296166-2ac3-4267-aeee-98e246c7a2c1".
>> [2025-07-05 19:33:36] [info] 19:33:36.092 [http-nio-8080-exec-17]
>> DEBUG o.a.g.rest.RESTExceptionMapper - Client request rejected: No
>> readable active connection for tunnel.
>> [2025-07-05 19:33:36] [info] 19:33:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Checking for expired or invalid
>> sessions...
>> [2025-07-05 19:33:36] [info] 19:33:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Session check completed in 0 ms.
>> [2025-07-05 19:34:36] [info] 19:34:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Checking for expired or invalid
>> sessions...
>> [2025-07-05 19:34:36] [info] 19:34:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Session check completed in 0 ms.
>> [2025-07-05 19:35:36] [info] 19:35:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Checking for expired or invalid
>> sessions...
>> [2025-07-05 19:35:36] [info] 19:35:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Session check completed in 0 ms.
>> [2025-07-05 19:36:36] [info] 19:36:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Checking for expired or invalid
>> sessions...
>> [2025-07-05 19:36:36] [info] 19:36:36.918 [pool-4-thread-1] DEBUG
>> o.a.g.rest.auth.HashTokenSessionMap - Session check completed in 0 ms.
>>
>> (This continues to the infinity)
>>
>> During this, two guacd processes are there
>> # ps aux|grep guac
>> root     2665853  0.0  0.2 764912 16144 ?        Sl   15:20   0:00
>> /usr/local/sbin/guacd -f -b 127.0.0.1 -L debug -l 4822 -p
>> /tmp/guacd.pid
>> root     2925052  0.0  0.2 777144 17320 ?        Sl   19:33   0:00
>> /usr/local/sbin/guacd -f -b 127.0.0.1 -L debug -l 4822 -p
>> /tmp/guacd.pid
>> root     2927526  0.0  0.0   6528  2340 pts/4    S+   19:36   0:00 grep guac
>>
>> The no readable active connection is a WTF.  During this on the
>> 192.168.1.103 there are no connection requests in the SSH log.
>>
>> I plan to check this on my test VM where i tested the Guacamole
>> install for 1.5.5 but i have omitted the test for 1.6, so i can
>> reproduce the issue with upgrading. As soon as i have time :(
>>
>> Thanks for your help :)
>>
>> Cs.
>>
>> On Sat, Jul 5, 2025 at 6:14 PM Nick Couchman <[email protected]> wrote:
>> >
>> > On Sat, Jul 5, 2025 at 9:27 AM Horváth Csaba 
>> > <[email protected]> wrote:
>> >>
>> >> Hi,
>> >>
>> >> The previous log was written by guacd with parameter -L debug, i only
>> >> copied from syslog.
>> >>
>> >> Now i tried again. In the below log i first connected to a VNC server
>> >> (so you can see the server is basically working) and then tried SSH,
>> >> but this time i got the message "Connected to Guacamole" and right
>> >> after the red ribbon with "Error occurred within the Guacamole
>> >> server..."
>> >>
>> >> # /usr/local/sbin/guacd -f -b 127.0.0.1 -L debug -l 4822 -p /tmp/guacd.pid
>> >> guacd[2658943]: INFO:    Guacamole proxy daemon (guacd) version 1.6.0 
>> >> started
>> >> guacd[2658943]: DEBUG:    Successfully bound AF_INET socket to host
>> >> 127.0.0.1, port 4822
>> >> guacd[2658943]: INFO:    Listening on host 127.0.0.1, port 4822
>> >> ...
>> >> guacd[2658943]: INFO:    Creating new client for protocol "ssh"
>> >> guacd[2658943]: INFO:    Connection ID is
>> >> "$0eb617c4-ec41-46a0-9be9-7d0705aea227"
>> >> guacd[2659316]: DEBUG:    Processing instruction: size
>> >> guacd[2659316]: DEBUG:    Processing instruction: audio
>> >> guacd[2659316]: DEBUG:    Processing instruction: video
>> >> guacd[2659316]: DEBUG:    Processing instruction: image
>> >> guacd[2659316]: DEBUG:    Processing instruction: timezone
>> >> guacd[2659316]: DEBUG:    Processing instruction: name
>> >> guacd[2659316]: INFO:    User "@04f87cbf-6f45-4785-897f-5df0cdfd8fbc"
>> >> joined connection "�!A�" (1 users now present)
>> >> guacd[2659316]: DEBUG:    Client is using protocol version "VERSION_1_5_0"
>> >> guacd[2658943]: INFO:    Creating new client for protocol "ssh"
>> >> guacd[2658943]: INFO:    Connection ID is
>> >> "$ad924c87-097e-4f1b-b0ab-8e3788c0a7ab"
>> >> guacd[2659508]: DEBUG:    Processing instruction: size
>> >> guacd[2659508]: DEBUG:    Processing instruction: audio
>> >> guacd[2659508]: DEBUG:    Processing instruction: video
>> >> guacd[2659508]: DEBUG:    Processing instruction: image
>> >> guacd[2659508]: DEBUG:    Processing instruction: timezone
>> >> guacd[2659508]: DEBUG:    Processing instruction: name
>> >> guacd[2659508]: INFO:    User "@ca7f6e87-53c6-4b6b-be2c-9e28255a04d9"
>> >> joined connection "�@�" (1 users now present)
>> >> guacd[2659508]: DEBUG:    Client is using protocol version "VERSION_1_5_0"
>> >> guacd[2659316]: ERROR:    User is not responding.
>> >> guacd[2659316]: INFO:    User "@04f87cbf-6f45-4785-897f-5df0cdfd8fbc"
>> >> disconnected (0 users remain)
>> >> guacd[2659316]: INFO:    Last user of connection "�!A�" disconnected
>> >> guacd[2659316]: DEBUG:    Requesting termination of client...
>> >> double free or corruption (out)
>> >>
>> >> guacd[2658943]: INFO:    Connection
>> >> "$0eb617c4-ec41-46a0-9be9-7d0705aea227" removed.
>> >> guacd[2658943]: DEBUG:    Unable to request termination of client
>> >> process: No such process
>> >> guacd[2658943]: DEBUG:    All child processes for connection
>> >> "$0eb617c4-ec41-46a0-9be9-7d0705aea227" have been terminated.
>> >> guacd[2659508]: ERROR:    User is not responding.
>> >> guacd[2659508]: INFO:    User "@ca7f6e87-53c6-4b6b-be2c-9e28255a04d9"
>> >> disconnected (0 users remain)
>> >> guacd[2659508]: INFO:    Last user of connection "�@�" disconnected
>> >> guacd[2659508]: DEBUG:    Requesting termination of client...
>> >> double free or corruption (out)
>> >> guacd[2658943]: INFO:    Connection
>> >> "$ad924c87-097e-4f1b-b0ab-8e3788c0a7ab" removed.
>> >> guacd[2658943]: DEBUG:    Unable to request termination of client
>> >> process: No such process
>> >> guacd[2658943]: DEBUG:    All child processes for connection
>> >> "$ad924c87-097e-4f1b-b0ab-8e3788c0a7ab" have been terminated.
>> >>
>> >
>> > There are a few things that jump out to me here:
>> > * First, the connection name or UUID appears to be mangled, as if 
>> > something is getting messed up with that. I'm not sure if this is an 
>> > artifact of copy/paste in e-mail, or if it really shows up that way in the 
>> > log?
>> > * Second, something is stopping traffic between Guacamole Client and 
>> > guacd. It's not entirely clear what, but the "User is not responding" 
>> > message indicates that guacd has stopped receiving its regular pings from 
>> > the client-side. This is likely related to the next issue (the double-free 
>> > or corruption) in some way or another, though it isn't exactly clear why.
>> > * Finally, the double free or corruption message is interesting as it 
>> > indicates that we've a bug somewhere in the code that is trying to free 
>> > something that has already been freed. Whether this is causing the issues 
>> > you're seeing or is just a byproduct or unrelated bug is unclear.
>> >
>> > The next things I'd suggest are:
>> > * Look for indications that you're getting a segfault in the guacd process 
>> > somewhere - any message in dmesg or other log facilities that indicate 
>> > that the guacd process is crashing? If so, get a stack trace of that crash 
>> > and see if you can post the contents of the stack back here.
>> > * Look at network traffic between Guacamole Client and guacd, and between 
>> > guacd and the SSH server, and see if something is shutting down the 
>> > connection for some reason. The fact that guacd is saying the client 
>> > stopped responding indicates the potential that something network-related 
>> > may be amiss.
>> > * Look at the Guacamole Client logs (Tomcat) and see if there's anything 
>> > in those logs that indicates a reason why the conversation between the 
>> > browser and guacd is getting shut down. You may also need to put Guacamole 
>> > Client into debug mode to see better messages related to that.
>> >
>> > -Nick
>>
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