OpensSSH certificate for authentication
Hi, i have some strange things during connection via ssh gateway
Linux RDM 2026.2.1.4 does not use OpenSSH user certificates during authentication.
OpenSSH successfully authenticates using:
id_tpamssh + id_tpamssh.pub
(ecdsa-sha2-nistp256-cert-v01@openssh.com)
RDM loads the private key successfully but only offers ecdsa-sha2-nistp256 instead of ecdsa-sha2-nistp256-cert-v01@openssh.com.
SSH debug log confirms that the certificate is never offered, while OpenSSH offers ECDSA-CERT and authenticates successfully.
For example:
RDM:
Successfully loaded key: ... Starting public key authentication Validating public key: ecdsa-sha2-nistp256 Key is not accepted by server
OpenSSH:
Offering public key: ... ECDSA-CERT ... Server accepts key: ... ECDSA-CERT ... Authenticated using "publickey".
Can you please help me with this problem?
All Comments (1)
Hello,
Thank you for the detailed information and the debug logs.
Could you please verify the following setting in Remote Desktop Manager?
File → Settings → Session → Terminal → Algorithm Support → Host Key
Check whether the host key algorithm required by your SSH server is enabled.
If the required host key is already enabled and you still experience the issue, could you let us know what type of machine or SSH server you're connecting to (for example, Cisco IOS, Linux/OpenSSH, etc.)?
We've seen similar behavior in the past with some older Cisco devices due to their supported SSH algorithms, so knowing the server type will help us investigate further.
We look forward to your update.
Carl Marien