This is an issue with Openssh and how the keys are handled, you can either adjust the configuration or down grade ssh.
You could add the following lines to your ~/.ssh/config and/or sshd_config Host * HostKeyAlgorithms +ssh-rsa PubkeyAcceptedKeyTypes +ssh-rsa Thank You Sean Hulbert Founder / CEO Work Ph: 925.663.5565 Security Centric Inc. A Cybersecurity Virtualization Enablement Company We don't just run you through the motions, Our labs teach you how to think! System Award Management CAGE: 8AUV4 AFCEA San Francisco Chapter V.P. If you have heard of a hacker by name, he/she has failed, fear the hacker you havent heard of! CONFIDENTIALITY NOTICE: This communication with its contents may contain confidential and/or legally privileged information. It is solely for the use of the intended recipient(s). Unauthorized interception, review, use or disclosure is prohibited and may violate applicable laws including the Electronic Communications Privacy Act. If you are not the intended recipient, please contact the sender and destroy all copies of the communication. Content within this email communication is not legally binding as a contract and no promises are guaranteed unless in a formal contract outside this email communication. igitur qui desiderat pacem, praeparet bellum!!! Epitoma Rei Militaris From: Jorge Lopez [mailto:jorge.lo...@eu.equinix.com.INVALID] Sent: Tuesday, November 22, 2022 3:58 AM To: user@guacamole.apache.org Subject: OpenSSH-format private keys / Ed25519 Hi, with Rocky Linux 9 release we are unable to connect to our remote servers caused by host key type. This is the error traceback: Nov 22 10:18:13 lm2vergpckeys01 sshd[359955]: Connection closed by ip_address port 37578 Nov 22 10:18:31 lm2vergpckeys01 sshd[359962]: Connection from ip_address port 56553 on ip_address port 22 rdomain "" Nov 22 10:18:31 lm2vergpckeys01 sshd[359962]: Unable to negotiate with ip_address port 56553: no matching host key type found. Their offer: ssh-rsa,ssh-dss [preauth] We are using guacd docker image with our own client development. Is there a workaround without modify this in remote server (security requisites) and enable in guacd? When is guacd v1.5 expected to be released in which I have seen in the code that this is fixed? Thanks Jorge López Díaz Managed Services Operations Senior Analyst EQUINIX | Calle Valgrande 6, 28108, Alcobendas, Madrid, España E <mailto:jorge.lo...@eu.equinix.com> jorge.lo...@eu.equinix.com | M +34682449912 <https://equinix.qualtrics.com/jfe/form/SV_5tZRNCGwOKna7A1> <https://twitter.com/equinix> <http://www.linkedin.com/company/equinix> <http://www.facebook.com/Equinix> <http://www.youtube.com/user/equinixvideos> This email is from Equinix (EMEA) B.V. or one of its associated companies in the territory from where this email has been sent. This email, and any files transmitted with it, contains information which is confidential, is solely for the use of the intended recipient and may be legally privileged. If you have received this email in error, please notify the sender and delete this email immediately. Equinix (EMEA) B.V.. Registered Office: Amstelplein 1, 1096 HA Amsterdam, The Netherlands. Registered in The Netherlands No. 57577889.