When the server recieves an UNIMPLEMENTED request over the ssh2 protocol it
responds claming that packet 0 is unimplemented:
	static void
	protocol_error(int type, int plen, void *ctxt)
	{
		log("auth: protocol error: type %d plen %d", type, plen);
		packet_start(SSH2_MSG_UNIMPLEMENTED);
		packet_put_int(0);
		packet_send();
		packet_write_wait();
	}

This is a violation of the protocol docs:
	byte      SSH_MSG_UNIMPLEMENTED
	uint32    packet sequence number of rejected message

to reproduce send the an auth request without requesting the auth service