Home firewall is intended to protect home network from the unauthorized access of our resources by external entities in the internet. Firewalls in computer networks are used to isolate the private network and hosts from danger posed by our neighbors. And it can help to keep something happening inside your network from spreading.
Traditionally, a firewall is used to protect one unit in a multi-unit building from a fire that occurs in an adjacent unit. The hope is that the firewall will isolate each unit from a disaster in one of its neighbors. Firewall in perimeter corporate network, and the personal home firewall in home network are designed based on the idea of protecting the inside from what is happening “out there”.
The main purpose of the firewall for the corporate and home firewall is a protection, why you need a protection. In order to meet the three principles—confidentiality, integrity, and availability—you need to address the risks you’ve identified. This may mean you need to be protected from the wide-open Internet. It’s a scary place out there. You may also need to isolate select hosts from the rest of your network. The threat of insider intrusion is still very real, and firewalls can help here too.
How does a firewall protect you? In its simplest form, a firewall examines your communications requests (network traffic) and decides, based on rules you have defined, what is and is not allowed. Home firewall and business firewalls are very straightforward function – on paper, anyhow. Complications are introduced by the different ways to achieve this goal. And each method has its own strengths and weaknesses.
Traditionally, corporations have firewalls only at the perimeter of the network – where the corporate network meets the Internet. However, the traditional network is changing. Users connect from home with high-speed Internet connections like cable modems, and sensitive data is being stored on local hard drives. These changes often make it necessary to consider protecting the local host with its own firewall software. And this is where personal home firewall software plays a role.
What Do Firewalls Do?
As pointed out earlier, a home firewall protects you from the actions of others. Generally, we are trying to restrict access by remote users and systems. From a technical perspective, a firewall intercepts traffic to and from the network and passes it on according to a predefined set of rules. Some firewalls act on behalf of their clients, some simply examine the packet contents against the rule set.
When Are Firewalls Necessary?
Firewalls are necessary when you need to protect resources on a specific host from access by remote users. You could lock down your computer so that it will not accept incoming connections by carefully examining each application and stopping unnecessary services. This is much easier said than done, even on Linux systems that allow the user more control over the operating system. As a result, a personal home firewall can allow you to leave applications running as installed and rely on the firewall to block incoming connections.
On small networks, you can sometimes protect the entire network through a single gateway host with personal home firewall software installed. Some products can even restrict access to Internet resources by user, allowing you to control your own users’ ability to access different remote services. You may want to be sure that your 16-year-old cannot use FTP services while you are able to. Many types of wireless routers such as WRT610N Linksys and WNDR3700 wireless routers have the parental control features.
Firewalls are necessary to protect any network from outsiders. Personal home firewalls are useful when you have a small number of hosts to protect, a single PC, or to supplement the perimeter protection of a firewall.
Where Are Firewalls Used?
In business class or large corporate networks, a firewall is used at the Internet gateway. Firewalls can also be used to isolate different workgroups within the organization. You might use a firewall to protect the finance department’s systems from other corporate users.
On a smaller scale, personal home firewalls are used on laptops to provide protection when they connect to unprotected networks such as those provided by some hotels. See also tips working in hotspots. Home computers also can benefit from a firewall. Internet service providers (ISPs) do not provide any protective services for their customers at this time, so you will need to provide your own protection. Finally, select hosts with sensitive data within an organization may benefit from personal home firewalls as well.
Who Needs a Firewall?
There are many different places where a personal firewall can be handy.
- Home users, especially with always-on Internet connections
- Corporate users with laptops. If laptops are used to connect to the Internet remotely, especially on unprotected networks. If the user is only ever dialing in to the corporate network directly, the risk is likely low, but high-speed hotel room connections are very risky.
- Corporate hosts containing sensitive data. Remember that internal users could be trying to obtain unauthorized access to those hosts also. They won’t be stopped by a corporate firewall at the perimeter, so you’ll need some other way of protecting the host.
If you connect your computer to a network, you are at risk. If it is a home network with a limited number of computers that you control completely, maybe you’re okay. Any connection to the Internet will compromise that network, though. You simply cannot know who is going to try to connect to your computer on the Internet. That is why you need a firewall at home.
Suggested readings:
- Firewall ports
- Firewalls security guidelines
- Sample risk assessment
- Business continuity and disaster recovery plan
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