Issue with SSH connection

Hi!

I’m facing a problem with thinllinc host key

when any user try to access my server this message pops up
can anyone help this poor human being ?

WARNING - SECURITY ISSUE!
The host key received by the server for the agent you are about to connect to does not match the host key reported by the agent.
This usually means there is a third party attempting to intercept the communication between you and the server.
Please notify the system administrator about this issue!
You will not be connected to the system for now.

Hi @daniel.Braun

Welcome to the forum.

This error can occur when the ThinLinc master and client disagree on which agent server you should be connecting to.

This normally means that the agent hostname is resolving to a different IP for the client than for the master.

How does your ThinLinc setup look? Do you have a single machine, or one master with several separate agents?

Check the value of the parameter agent_hostname in /opt/thinlinc/etc/conf.d/vsmagent.hconf on each agent, and make sure this resolves correctly for both master and client. If this doesn’t help, please feel free to send through the master and agent logfiles /var/opt/vsmagent.log and /var/log/vsmserver.log, and the relevant client log file.

Hi @aaron ,

Thank you for your support! Unfortunately, I wasn’t able to identify the issue with the VSMAGENT.hconf file.

I’ve observed that the problem occurs once a week, specifically every Monday. My team and I have analyzed the issue but haven’t been able to determine the root cause. As a temporary measure, we’ve been rebooting the server, which resolves the issue and restores normal functionality.

Below are the files vsmagent and vsmserver

2024-10-06 00:00:04 INFO vsmagent: VSM Agent version 4.15.0 build 3358 started

2024-10-06 00:00:04 INFO vsmagent: My public hostname is 192.168.26.145
2024-10-07 09:29:19 INFO vsmagent.session: Verified connectivity to newly started Xvnc for adriano.lucio
2024-10-07 09:57:15 WARNING tl-session: tl-xinit was terminated by signal 1
2024-10-07 09:57:16 INFO vsmagent: Got SIGTERM, signaling process to quit
2024-10-07 09:57:16 INFO vsmagent: Terminating. Have a nice day!
2024-10-07 09:57:16 WARNING tl-session: pam_close_session failed: 10 (User not known to the underlying authentication module)
2024-10-07 10:01:33 INFO vsmagent: VSM Agent version 4.15.0 build 3358 started
2024-10-07 10:01:33 INFO vsmagent: My public hostname is 192.168.26.145
2024-10-07 10:01:33 WARNING vsmagent: /opt/thinlinc/libexec/ssh-keyscan failed
2024-10-07 10:04:07 WARNING vsmagent.sessions: Broken session for user adriano.lucio, tl-session process 616637 does not exist
2024-10-07 10:04:08 INFO vsmagent.session: Verified connectivity to newly started Xvnc for adriano.lucio
2024-10-07 10:11:33 WARNING vsmagent.sessions: Broken session for user administrator, tl-session process 6055 does not exist
2024-10-07 10:11:33 WARNING vsmagent.sessions: Broken session for user ruhan.ponce, tl-session process 18818 does not exist
2024-10-07 10:11:33 WARNING vsmagent.sessions: Broken session for user luiz.soares, tl-session process 215029 does not exist
2024-10-07 14:19:11 INFO vsmagent.session: Verified connectivity to newly started Xvnc for luiz.soares
2024-10-11 09:17:01 INFO vsmagent.session: Verified connectivity to newly started Xvnc for adriano.lucio
2024-10-11 09:20:05 INFO vsmagent.session: Verified connectivity to newly started Xvnc for administrator
~
~
~
~

2024-10-06 00:00:04 INFO vsmserver: VSM Server version 4.15.0 build 3358 started
2024-10-06 00:00:04 INFO vsmserver.license: Updating license data from disk to memory
2024-10-06 00:00:04 INFO vsmserver.license: License summary: 10 concurrent users. Hard limit of 10 concurrent users.
2024-10-06 00:00:04 INFO vsmserver.session: Loaded 3 sessions for 3 users from file
2024-10-06 00:00:05 WARNING vsmserver.loadinfo: [Errno 111] Connection refused talking to VSM Agent 127.0.0.1:904 in request for loadinfo. Marking as down.
2024-10-06 12:00:04 INFO vsmserver.license: Updating license data from disk to memory
2024-10-06 12:00:04 INFO vsmserver.license: License summary: 10 concurrent users. Hard limit of 10 concurrent users.
2024-10-07 00:00:05 INFO vsmserver.license: Updating license data from disk to memory
2024-10-07 00:00:05 INFO vsmserver.license: License summary: 10 concurrent users. Hard limit of 10 concurrent users.
2024-10-07 08:58:27 INFO vsmserver.session: User with uid 167436 requested a reconnection to 127.0.0.1:12
2024-10-07 08:58:27 INFO vsmserver: Verifying session 127.0.0.1:12 for luiz.soares
2024-10-07 08:58:27 INFO vsmserver: Session 127.0.0.1:12 for luiz.soares is alive and ready for reconnection
2024-10-07 09:29:19 INFO vsmserver.session: User with uid 160552 (adriano.lucio) requested a new session
2024-10-07 09:29:19 INFO vsmserver.session: Session 127.0.0.1:13 created for user adriano.lucio
2024-10-07 09:30:28 INFO vsmserver.session: User with uid 1000 requested a reconnection to 127.0.0.1:11
2024-10-07 09:30:28 INFO vsmserver: Verifying session 127.0.0.1:11 for administrator
2024-10-07 09:30:28 INFO vsmserver: Session 127.0.0.1:11 for administrator is alive and ready for reconnection
2024-10-07 09:33:22 INFO vsmserver.session: User with uid 1000 requested a reconnection to 127.0.0.1:11
2024-10-07 09:33:22 INFO vsmserver: Verifying session 127.0.0.1:11 for administrator
2024-10-07 09:33:22 INFO vsmserver: Session 127.0.0.1:11 for administrator is alive and ready for reconnection
2024-10-07 09:48:20 INFO vsmserver.session: User with uid 160552 requested a reconnection to 127.0.0.1:13
“vsmserver.log” 67L, 6778B
[/quote]

@daniel.Braun very strange. I can’t see anything in the log files to explain what’s going on here. It would pay to check the client log file as well.

Are you also being asked by the ThinLinc client to re-verify the host fingerprint every Monday as well?