The term firewall gives you some understanding of its purpose when it comes to protecting your computer. It is basically a wall that is set up in the internal components to protect your computer from various malicious acts.
The firewalls that are used with the modern technology are application firewalls. This means that the technology that it's based on has to have the ability to be able to intercept the threat as well as understand what it is built on in order to be able to stop it. It is capable of blocking any processes that it has identified as being unauthorized. The fire wall technology is able to scan what processes are taking place on the computer and block them if they feel that there is a threat. This is particularly important when you are trying to protect your home network of computer devices. Firewalls have the ability to be able to block viruses as well as worms and Trojans. One of the problems and challenges with the firewall technology is that there are new threats becoming available every day and it is difficult for the technology to be able to keep up with this.
You will sometimes hear about firewall protection being applied inside out and outside in. The main purpose of the firewall is to stand on guard against any information that is coming into your computer system from the outside. One of the weaknesses that was determined is that the old type firewalls were providing protection by scanning information that was already in the computer that was coming from an internal host. This is not usually a problem that the home computer user has to deal with but is more applicable to large corporations that are running off of large infrastructures. This is a why there is often a big difference in what the home user will purchase for their antivirus programs compared to what businesses will use because of the threats can be at a much higher level for businesses compared to the home user.
Another problem that has been identified with the firewall technology is that it doesn't provide good protection from damage being created through emails being compromised. Most are well aware of the word phishing and what this means is where hackers will send out enormous amounts of emails that will create havoc for anybody that opens them. Usually the spam filters that come in the antivirus programs will deal with the email issues. One problem that is having it to be dealt with is called spear phishing. This is where one individual is being targeted and information about that person is being gathered. This is one that is addressed with the additional security features that are built-in to a quality antivirus program.
The firewall cannot protect your computer from being infected from malware that may be present on a site that you have visited when browsing the web. Again this is why you need antivirus software that has this added protection built into it. The firewall is definitely an important piece of technology but is not something that one should solely rely on for all of their computer protection.