Firewalls are used to protect the Intranet from intrusion and for security. But one of my friend told me that if we use firewall then the threat of virus attack is also minimised. Also whether the system running the firewall is safe from attackers and virus.
Yes. Firewalls are used to protect the Intranet from intrusion and for security. It will help against a direct attack to place a virus on your system.
But, it doesn't stop email viruses, unless your firewall has an option for anti-virus. You still need to have anti-virus on your desktops.
For example, I have a friend who has a Sonicwall that has Macafee anti-virus on it. I suggested that he put Norton on his desktops. Sometimes Norton is better at protecting against some viruses and vice versa. This way he get's the best of both worlds.
You still need to be careful whenever you open any email with an attachment.
If you are talking about an individual firewall, such as zone alarm, the system could still get infected without an anti-virus program. A self contained hardware firewall typically is safe.
When it comes to security, you have to understand the concept of 'defense-in-depth', there is NO cure all solution to your security problems...
a firewall is ONE component in a security solution.. the other important ones are anti virus protection on each desktop REGULARLY updated, intrusion detection system, a good security policy and perhaps even personal firewalls on each desktop
the idea is to layer your defence
there is no point having a firewall if someone on the network has a modem answering calls allowing anyone to dial in.. or people who's virus defs are 3 years old.
People feel that you shove a firewall in the network and voila you're safe ! It couldn't be further from the truth.. in fact a badly configured firewall is probably a bigger problem than no firewall at all.
Now that i've finished my paranoid IT security professional rant, just remember, there are people who get paid lots of money to implement security solutions, their jobs involve much more than merely putting up firewalls.
ps. I think its the ominous image the word 'firewall' conveys.. it just sounds so impenetrable and deadly lol !
You need to look not at viruses, but worms, Trojans - giving out your email address to anyone is always a risk. Your identity can be stolen just giving your Credit Card number to a website. There is no way to be completely safe. You do need to take reasonable precautions, however.
The problem with Firewalls, as Sahirh, mentions, is that people think they are now safe. The problem is there are various types of firewall that solve problems in different ways. You have hardware firewalls and personal firewalls. Each with a variety of settings.
In your post you mention whether the system running a firewall is safe. I assume you are talking about personal firewall or a Linux Firewall. Personal firewalls really only only protect the system it is on. If you have multiple computers, each will need one. And it uses up workstation workstation resources, like any other service.
As was mentioned, security experts get paid very well for what they know as it a complete solution is fairly complicated depending on the situation.
For the home, I prefer a comodity firewall device (linksys, soho etc), which are fairly cheap and do a pretty good job. You just have to remember not turn off the mind and assume that they are a Panacea.