Subject: Re: kex error : no match for method mac algo

From: Danie de Jager <[email-masked]>
Date: Mon, 18 Feb 2019 11:07:37 +0200

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 [email-masked]
,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256
Ciphers [email-masked],[email-masked],
[email-masked],aes256-ctr,aes192-ctr,aes128-ctr
MACs [email-masked],[email-masked],
[email-masked],hmac-sha2-512,hmac-sha2-256,[email-masked]

Client sshd config:
Client using default sshd config

or

HashKnownHosts yes
HostKeyAlgorithms [email-masked],
[email-masked],ssh-ed25519,ssh-rsa,
[email-masked],
[email-masked],
[email-masked]
,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256
KexAlgorithms [email-masked]
,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256
MACs [email-masked],[email-masked],
[email-masked],hmac-sha2-512,hmac-sha2-256,[email-masked]
Ciphers [email-masked],[email-masked],
[email-masked],aes256-ctr,aes192-ctr,aes128-ctr

Error:
"kex error : no match for method mac algo client->server: server [
[email-masked],[email-masked],
[email-masked],hmac-sha2-512,hmac-sha2-256,[email-masked]],
client [hmac-sha1]"

or sometimes

"crypt_set_algorithms2: no crypto algorithm function found for
[email-masked]"

Let me know if I can provide more information.

Regards,
*Danie de Jager*