a doubt in X-windows and security

Q1. sometimes when i get into GNOME by running startx at the command prompt i get a desktop with no icons..and sometime later or maybe a few logons later i get a desktop with the icons in place..and this keeps repeating..what could the cause be?how can i fix it?

Q2. recently i had a problem with my GNOME desktop on one of my computers..when i get into GNOME i get a message that i am not using a GNOME complaint window manager..but i never changed it in the first place..further i used to get a lot of minimised windows on the panel and funny looking windows on the screen..how could that have happened?? then i opened GNOME control center and when i clicked window managers i found out that twm was my current window manager..so i changed it to sawfish and then the problem disappeared..but that was only for a few days..the problem came back sometime later..again i got all the above mentioned message and symptoms..when i checked i found out the twm was running instead of sawfish..but this time when i changed the window manager to sawfish it refused to change..can anyone help with this?

Q3.on a fully functional Linux machine how can i reinstall X-windows..that is, i want the kernel and filesystem intact..but i want to reinstall the X-Window..so how can i first uninstall the existing X-Windows and then reinstall it..what are the packages that i should uninstall and then re-install?

Q4. how can i setup an Xserver to accessed by Xclients?what are the security issues involved

x

check out fink..I wouldn't use remote x windows ...big security issues

Dunno about your non-security related questions.

As far as security and X is concerned:

- X can allow remote applications to connect to your display, this is undesirable if they're untrusted.
Most Linux distros these days turn off remote X by default so that only authorised clients can connect, which is ok.

- If you do "xhost +" (to turn off X authentication), be sure to be behind a firewall

- If you do use X across the public internet, be aware that any keystrokes, etc sent to a remote app are sent unencrypted (unless u use ssh tunnelling)