Connection fails with "Fatal: Unable to negotiate a key exchange method" message

FAQ

The problem may be related to the potentially incompatible changes introduced in OpenSSH 6.7 (included in Copssh 5 and higher) to remove unsafe algorithms.

  • Add following line to the [server] section of the configuration file bin/copsshcp.config:

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

  • Restart the service via Copssh Control Panel