Re: CLI connection lost
Someone else may know, but I have not heard of a fix for this if you are experiencing it. What version of 6.4.x are you on? Make sure you get on 6.4.2 if you're not, because 6.4.1 was horrendously buggy for us.
Workaround: use an SSH client like PuTTY and make sure SSH is enabled on the management interface.