How does a linux live Cd work?

Hi, I have been using Ubuntu and Knoppix for a while on live Cd and i have always wondered how they work from just a cd. Also should you have a Av or firewall running while using these live cds? Thanks for any help

 

i wouldnt worry much about having a firewall or antivirus if I were running any version of linux.

 

Big thanks WSFuser, Take care.

 

All the components are uncompressed and loaded into memory as needed from the CD and everything runs from there. It's a rather safe solution for navigating the net, as once the PC is off and the memory is flushed everything is gone.

 

I would worry TOO much about having a firewall in ANY version of linux.
Who in the world told you that?Maybe wanted to say a "live" version of linux?
Most Linux distros can get hacked pretty easily,especially if someone is a novice user.
I wouldn't worry about a firewall if all I was running was a live cd:
shutdown -h now and poof!everything,including hackers,is pretty much gone.
(Although even this is not actually true,it's just kind of harder to exploit.
Example:after gaining root access to your unix system,
someone could load a kernel module that gives write access to your windows partition.
Also,I bet there is a way to write info directly in the boot sector of the hard drive,
even from inside a live cd:so that when trying to restart in windows...)
For a hard disk installation,a firewall is 100% REQUIRED.
Anti-virus is also a necessity for hard disk installations,
with the great difference that there are NO 0-day linux virus outbreaks:
most viruses are written for win32,so you can browse nasty sites,
say "infected" with variants of the recent .wmf exploit and no problem so ever.
You just don't have to check/catch up with updates every once in a while.
And there's no need for blah1+blah2+blah3 etc. software to be installed to be protected,
you learn how the filesystem works,study VERY well the administration tools,
the configuration files and their syntax,and then you just live the way every user should live:
log in,do your job,browse what you want,finish the job and log out.

 

I would consider running a AV if I had Linux and why not since AVG has a free version that is for Linux. http://free.grisoft.com/doc/4040/lng/us/tpl/v5

I would also use a firewall, but together that would probably be enough protection for Linux. Though looking into ways to protect yourself from rootkits would be wise as well. Linux can be compromised just like Windows, though it's not as common with Linux. Hey, your better safe than sorry IMO.

 

people run windows without an antivirus and considering how much less linux is targeted, could u not also run linux without an antivirus? also afaik AV for linux are on-demand anyways.

edit: as of yet i have not installed any linux so i have to get past that before even trying an AV or any other kind of program.

 

It all depends on how much "lunatic" someone is.
Firstly let me say that I am not an expert,i'm just an "ex-Windows regular user",slowly migrating to Unix.
For example,this moment i am posting from my pretty-well known/familiar Windows pc.
To describe it in simple terms:Unix is not an just a operating system,it is an IDEA.
This can get you to the best experience/quality or equally the worst:it's all about WHAT is your achievement.

Do you just want safe-browsing?
Then,just download a Knoppix/whatever live CD:Your wish will pretty much come true,my master.

Do you want a system that can be configured to be really secure?
Install (the official versions of) FreeBSD,GNU/Debian or SlackWare.
These are the TRULY good distros,and their code is audited by lots of hundreds of experts/hackers.
There might also be other distros that are secure,and almost definitely more secure than Windows,
but that has NOT been proven over time.
Don't expect that a live cd that someone made in his free spare time,
and uploaded it in Freshmeat/SourceForge,can be really secure.
In fact,it could have very serious "holes",that never get noticed by other people,
simply because it is developed by 1 single person and/or maybe some of his/her friends.

Are you really-really paranoid about security/privacy?
Want the ULTIMATE solution,one that is also funded by the U.S.Army?
Then install OpenBSD,configure the internal firewalls,do daily cvsups(or whatever they use),
also get a 2nd disk-less machine running something like MonoWall,
and put a Snort in it(if it doesn't come with it pre-installed),
so you can watch the suspicious intruding packets in real-time
(although i bet that there won't be a lot of them,
since they will already have been discarded by the firewalls...)

I pretty much write all this,because i 've seen a lot of people having a myth about Unix:
others think they are only for hackers,others think it's completely impossible to learn them,
and a lot of people think that Unix is all about not having an AV,a firewall or things like that...
it's not true:it's just that the Unix community has pretty much SOLVED basic things like that...
yeap,you've read that right:"basic",so they just move on in solving other problems,
which might be even MORE serious/difficult/dangerous than the ones in the Windows world...
(also notice the difference in the semantics:"world' vs "community").
That's the Unix's way...hard to learn,but VERY EASY to try.
Hard to configure it in the right way(and also to meet your taste),
but it can be configured to suit perfectly EVERYONE 's taste:
The price of this,I already mentioned:it is an IDEA.
You have to be committed to that and spend a lot of time,
before this "idea" actually becomes your daily pc 's reality...

 

ur explanation makes sense and seems fair, thanx for elaborating that idea