Package: client

The client does not support chacha20 as I get this error when I try to connect to the X2Go server. I did harden my SSH configuration as guided by Mozzila
https://infosec.mozilla.org/guidelines/openssh

When I use defaults it works fine. It seems that the library used by X2Go is missing some newer methods.

Config:
server ssh config:
KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256
Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com

Client sshd config:
Client using default sshd config

or

HashKnownHosts yes
KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256

Error:
"kex error : no match for method mac algo client->server: server [hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com], client [hmac-sha1]"

or sometimes

"crypt_set_algorithms2: no crypto algorithm function found for chacha20-poly1305@openssh.com"

Let me know if I can provide more information.

Regards,
Danie de Jager