> For the complete documentation index, see [llms.txt](https://docs.devolutions.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.devolutions.net/powershell/remote-desktop-manager-powershell/ssh-algorithm-support.md).

# SSH algorithm support

The following error message can appear when opening a Secure Shell (SSH) connection in Remote Desktop Manager: "An unexpected error has occurred: Error code SSH\_FAIL\_NO\_MATCH (-3006) Unable to find a matching algorithm with the SSH server".

### Local solution for one entry

{% hint style="warning" %}
Remote Desktop Manager now has a selection of algorithms for the SSH session type. Please note that the **unsecured** ones are not enabled by default. We therefore recommend to check the algorithms directly on the server for security purposes. Otherwise, follow the steps below to resolve this issue.
{% endhint %}

1. Right-click on the problematic entry and select ***Properties***, then go to ***Common*** – ***General.***
2. In the ***Advanced*** tab, set the ***Algorithm support*** option to ***Custom***.

![](https://cdnweb.devolutions.net/docs/RDMW4165_2024_3.png)

3. Click on the ellipsis button (***...***) that appeared to the right of the ***Algorithm support*** setting.
4. In the new ***SSH*** window, select the missing algorithms from the list.

   <div data-gb-custom-block data-tag="hint" data-style="warning" class="hint hint-warning"><p>Make sure to go through the algorithms in all tabs before proceeding.</p></div>

   <figure><img src="https://cdnweb.devolutions.net/docs/RDMW6109_2024_3.png" alt=""><figcaption></figcaption></figure>
5. Click ***OK*** in the ***SSH*** window, then ***OK*** again in the window of the entry properties.

   <div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><p>It may be necessary to restart Remote Desktop Manager for the solution to take effect.</p></div>
6. Test the connection. If the connection still does not work after enabling the algorithms, return to the ***Advanced*** tab in the entry properties, and check the ***Skip environment variable setup*** box. Click ***OK*** to effectuate the change.

![](https://cdnweb.devolutions.net/docs/RDMW6111_2024_3.png)

### Global solution for all entries

It is also possible to globally reactivate all the algorithms in Remote Desktop Manager via the ***File*** – ***Settings*** – ***Entry types*** – ***Sessions*** – ***Terminal*** – ***Algorithm support*** menu. Select the missing algorithms, then click ***OK***.

{% hint style="warning" %}

* Make sure to go through the algorithms in all tabs.
* It may be necessary to restart Remote Desktop Manager for the solution to take effect.
  {% endhint %}

![](https://cdnweb.devolutions.net/docs/RDMW4168_2024_3.png)

### Custom Powershell command script

If the issue persists on a specific entry, run the following PowerShell script in Remote Desktop Manager.

1. Right-click on the problematic entry, then select ***Edit*** – ***Edit (special actions)***.
2. In the ***Edit – Special action selection*** window, select the ***Custom PowerShell command*** general special action and click ***OK***.

   ![](https://cdnweb.devolutions.net/docs/RDMW4375_2025_2.png)
3. Paste the following script in the ***Command*** field:

   ```powershell
   $Connection.Terminal.AlgorithmSupportMode = "Custom"
   $Connection.Terminal.SshAlgorithmCipherList = "aes256-gcm@openssh.com=True;aes128-gcm@openssh.com=True;aes128-cbc=True;aes192-cbc=True;aes256-cbc=True;rijndael-cbc@lysator.liu.se=True;3des-cbc=True"
   $Connection.Terminal.SshAlgorithmHostKeyList = "ssh-dss=True"
   $Connection.Terminal.SshAlgorithmKexList = "diffie-hellman-group14-sha1=True;diffie-hellman-group-exchange-sha1=True;diffie-hellman-group1-sha1=True"
   $Connection.Terminal.SshAlgorithmMaclist = "hmac-sha1-96=True;hmac-sha1=True;hmac-md5-96=True;hmac-md5=True"
   $RDM.Save();
   ```
4. Click ***OK***.

   ![](https://cdnweb.devolutions.net/docs/docs_en_kb_KB4758.png)
5. A notification should confirm the success of the script. Click ***OK*** and retest the session.

### See also

* [Devolutions Academy – Configure SSH algorithm support](https://academy.devolutions.net/student/page/3288493-configure-ssh-algorithm-support?sid_i=0)


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