No common kex alg: client 'diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1', server 'curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1'

Al querer conectarme por ssh desde un cliente ssh solaris a un servidor ssh linux me aparecía lo siguiente:

no common kex alg: client 'diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1', server 'curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1'

Para permitir la conexión editamos el sshd_config del servidor ssh:

vi /etc/ssh/sshd_config

Al final agregamos lo siguiente:

KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521

Reiniciamos el servicio ssh del server:

/etc/init.d/ssh restart

Y ya nos deja conectarnos correctamente.