Why Linux needs firewall?

Question

I don`t know much about Linux, I thought it was safe like macs then no need for firewall. But I see all the firewall softwares around for Linux. ( I recently installed Kubuntu Dapper Drake 6.06).

Answer 1

Linux and Mac OS aren't safe. They're arguably safER than Windows; reasons for if they are and why vary. But no system is foolproof. Hence the firewalls, anti-spyware and anti-virus software available for Mac and Linux.

Answer 2

There's only one firewall on Linux systems. That's iptables (on the newer kernels). Everything else is just configuration tools (if you don't want to edit by hand).

Why does Linux need a firewall at all?

Consider what not having a firewall means. You can't regulate connections between your computer and other computers at all. Linux is commonly used as a server. For example, linux users may run http servers, ftp servers, ssh servers and so on. Now, consider a malicious third party who wants to gain access to your system. He decides to target your ssh server. He sets up a program that tries to brute force guess the password to access your ssh server.

Are you at fault here? No. You just want to be able to ssh to your own system. Is linux at fault here? No. It's like saying a bank is at fault if a robber decides to attack the place. It's the other guy who wants to break into your computer. What could you do to stop him?

Don't let him connect to you at all. That's where a firewall comes in. You need a firewall that stops any connections from whoever wants to break into your computer.

Also, consider that Linux can be setup as a firewall itself. Instead of running a firewall on a Windows computer, you setup a real firewall on a Linux computer. You connect your windows machine to the linux computer, and the linux computer to the internet. In that sense, your linux computer is a router. Your linux computer has a firewall that can protect your windows firewalls.

This isn't unusual. Commercial routers you pay for with lots of $$$ run Linux and a firewall on them.
EDIT:

Also worth mentioning the purpose of a firewall. How do you think a firewall "protects" a computer? What do you think a firewall does? They aren't magical shields.

All they are is a way of regulating network connections. Having a firewall doesn't make you any safer if 1) you don't have any connections to monitor or block and 2) if you setup stupid rules for the firewall

That's why many power users live just fine without a firewall on Windows. They don't have any open servers, and anything they have is well protected. If you have no spyware on your computer, and you run no servers, for the average consumer a firewall does absolutely nothing.

Answer 3

Every operating system (past, present, and future) is vulnerable to hackers and viruses. Mac and Linux *ARE* safer than Window$, but only because more people use Windoze. Because more people use it, the hackers and the virus makers tend to focus on it. That's why we still need firewalls, virus checkers, etc. It's just that if a Window$ user and a Linux user both install none of these things the Windoze user is just *more* likely to get attacked.

When the world finally wakes up to the fact that they are getting ripped of by Micro$oft and Apple and turn to open-source operating systems like Linux, Linux will get lots more viruses than it does now, probably in the sorts of numbers that Window$ currently gets. But it will still be waaay better than any crap that M$ can come up with. And it will probably deal with the viruses better too.

Answer 4

Any OS, if you are not careful installs many softwares and lot of accounts, which you may not aware of it and require it.

For example, Nfsd, portmap, sendmail sshd etc.
Any of these softwares can have vulnerabilities or default accounts have a simple passwords to access as normal user.
After allowing as normal users, some software venerabilities
make it that to gain root access ( apart from server softwares)

Any OS is bad with default install. You need to stop services or use firewall. Advantage with Linux is if you are familiar it
is easy to configure firewall.

Answer 5

You may live in a safe neighbourhood, but you would still want a lock on your front door in case something happens, right ?