locking the system

[mfghazi]

How can we lock the system therefore no program will stop execution and the system cannot be used by any unauthorized person?

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Ghazi, Muhammad Farhan

[scott_R]

There is no perfect way to lock a system. If someone is desperate enough to get in, they will. The best thing you can do is set up enough barriers to dissuade them. Also, it depends on your personal situation. What are you using the system for? Is it open to the public, or just a limited number of people? Is it connected to the internet? Can you protect the hardware by hiding it, or do you need it to sit in the open?

If you think about it, there are so many ways to break into a system. Some of the common ways are to capture passwords, reboot the computer with a floppy, or even take the whole computer home to work on it in your own time.

For most people, a simple screensaver password will do the job. If there is a chance someone may try to reboot the computer, you can use the bios, and disable booting from a floppy, as well as add a bios password. If you're really paranoid, you can even buy items that will hold the computer in place so no one steals it.

Security is one of those things that is best determined by you. You can make your system nearly bulletproof, but if you do too much, there is a chance you will make it too hard for you to use it yourself. The best thing for you to do is to read up about it (there are many sites on the web, just do a search), and work at it bit by bit.

Good luck! http://www.linuxnewbie.org/ubb/smile.gif

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RTFM=Rewrite The F***ing Manual
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The snow's falling, and so is MS...:)

[mfghazi]

Thanks for the reply. I think I couldn't explain the problem. The way an NT machine can be locked, pressing the Crtl-Alt-Del keys and selecting the Lock Workstation button. Can we lock a Linux machine the same way. I'm not talking about physical locks and security issues. :p

[ch0wn]

ctrl+alt+del on an NT box is the same as logging out on a *nix box. both require a password to log onto the computer

[manual_overide]

not the same as loging out. Locking an NT station doesn't close your programs

Yes you can lock your linux screen, but it is different for each window manager. Poke around for a while. I'm sure you'll find it. I don't know of a way to lock a machine not running X, though.

[mfghazi]

Yes. I've seen some keyboards on which there's a key for locking the systems. But that person also don't know how to do it. :confused:

[Gnu/Vince]

How about xlock (for X) and vlock (console)??

[scott_R]

KDE has a "lock screen" option in the menu that allows you to drop into your screensaver without closing programs. Then you'll have to log back in before it will let you use the system again. It also allows programs to keep running. I use it for downloading game demos at work so my boss doesn't notice. :)

I beleive gnome has the same, but I'm not sure about other window managers.

[TaeShadow]

The problem with locking the X display is that someone can walk up and press Ctrl-Alt-Backspace and shutdown the X server, thereby gaining access to your account via the command prompt. I don't know if there's a way to prevent this.

[Strike]

You can just go to a virtual console and use vlock. Nothing can get past that short of rebooting or entering the password (that I know of).

[hndpaul]

Yes- to all the above! You can use KDE's "lock screen" on the K start menu, or vlock from the terminal. Since I use Gnome most of the time, I just use the "lock" icon on the bar at the bottom of the screen. ONe thing I have noticed is that if no screensaver is turned on, the lock option in Gnome doesn't work! I don't know why. In KDE, you can lock the screen independent of any screen saver and a user has to have the correct password or reboot the system to get out of it..but even then you have the password to put in again :D

Hope that helps!

Paul, UK

[mfghazi]

It worked in gnome using xlock. Thanks to all of you. :)