Resolved SSH Terminal Extension not working

[Paolo Percassi]

Server operating system version

AlmaLinux 8.7 (Stone Smilodon)

Plesk version and microupdate number

Plesk Obsidian Version 18.0.48, last updated on Nov 18, 2022 12:51 PM

Hi,

I manage 4 Plesk Obsidian servers. In three of them SSH Terminal Extension works fine. In 4th server the Extension worked since two days ago. Now, opening SSH Terminal from Tool & Settings I receive a looping message:

[email protected]: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).

Connecting via SSH to 4th server works normally if I connect from my MacOs Terminal or from any of the other my servers. Only from local extension won't work.

I looked file /etc/ssh/sshd_config comparing it between my servers, I reinstalled SSH Terminal Extension but the problem is always the same.

I also observed that, when I start the extension clicking Tools & Settings > SSH Terminal, Plesk regenerate the file root/.ssh/authorized_keys as well as they do all other 3 servers.

Any suggestion is welcome.

Thanks
Paolo

 

[Peter Debik]

Have you tried this?

https://support.plesk.com/hc/en-us/articles/4410634559250-It-is-not-possible-to-access-SSH-terminal-extension-via-root-user-in-Plesk-ssh-exchange-identification-read-Connection-reset-by-peer

 

[Paolo Percassi]

Thank you Peter,

yes, i've tried this but no solution.

It seems to me to be a problem in authenticating by Public Key but:

1. the error messages refers that logging by "publickey" is active as well as other methods
2. I've also tried to insert explicit "PubkeyAuthentication yes" in my sshd_config file

but... no solution.

 

[Peter Debik]

Do you see an entry "[ext-ssh-terminal]" in your Plesk panel.ini file?

 

[Peter Debik]

How to disable root access via the SSH Terminal extension for the Plesk administrator?

Applicable to: Plesk for Linux Question The SSH Terminal extension is available in Plesk 18.0.37 and later. With this extension, the Plesk administrator can access the SSH console on behalf of t...

support.plesk.com

 

[Paolo Percassi]

No, I don't see any section [ext-ssh-terminal] in my Plesk panel.ini file.

 

[Peter Debik]

O.k., summing it up then:
- SSH service is running
- SSH is working from the outside but not when Plesk SSH extension is trying it locally
- No limits on it are set in panel.ini
- Root access is permitted in sshd_config and sshd was restarted afterwards

I suggest to create a support ticket and allow supporters to check the issue directly on your server.

How to get support directly from Plesk?

Question How to get support directly from Plesk? Answer Lease-type Plesk licenses purchased directly from Plesk running on supported Plesk version include full free support. Perpetual-type license...

support.plesk.com

(30 days free trial)

Please also include a link to this thread in the support request.

 

[Paolo Percassi]

Solved.

I found this entry in my /etc/passwd file:

plesk-ssh-terminal:x:985:985lesk SSH Terminal:/usr/local/psa/var/modules/ssh-terminal:/usr/sbin/nologin

and I checked that this entry wasn't present before (I compared to a backup of 10 days ago).

So I removed the line from /etc/passwd file and my SSH Terminal inside Plesk returned to work fine.