Firewall is a protection net system based on hardware and software programs and manages incoming and outgoing traffic. It acts as a barricade between reliable net and other untrustworthy environment, such as the internet, controls accessing to net resources over a positive control model. In such a way, traffic provided onto the net is defined in the firewall policy, but all other data is denied.
Mechanisms of Firewall
- Packet firewall acts like a packet filter inspected transferred data between computers on the Internet. When traffic passes over a packet-filter firewall, its source and destination location, used protocol and target port number are verified with established set of rules. Any packet that isn’t specifically granted onto the net is dropped (for example, not forwarded to its destination).
This type of firewall operates on physical, data-link and network OSI model’s layers and addresses to transport layer in order to achieve a pointed location.
This technology isolates each packet that makes them vulnerable to spoofing and limits their capabilities providing more complex choices based on communication stage between hosts.
- Stateful firewall identifies packets’ connection state recording all passing traffic. This info used for granting or rejecting access established on packets’ history and speeding up transmit processing.
- Application-layer firewall secures servers and applications running on them. The firewall is able to block specific content, such as malware, and recognize when certain protocols are being misused.
- Proxy firewall operates at the application layer, prevents direct connections between both firewall sides. Either communication part is able to conduct sessions via the proxy which blocks or provides traffic based on its set rules. Proxy service runs for each type of net application supported by firewall, such as HTTP proxy for web services.
Types of Firewall
- Software firewalls are designed for old generation Operating systems which come without builtin firewall and provided access the Internet functioning as a gateway to a home net.
- Hardware firewalls are presented by routers with builtin Ethernet card and hub. Connecting these tools, devices can access the web.
Rules for using Firewall
- If you use a device at home, the most effective and important first step you need to take is protecting your machine turning on a firewall.
- Windows operational systems have a builtin firewall which turns on by default.
- If you have more than one gadget connected to your home net, it’s important to protect every device. You should have a hardware firewall guarding the net and use a software firewall on each machine to prevent the virus attack and its expansion if one of the devices has been infected.
- If your gadget forms a part of a business or other organizational net, you need to keep the policy established by the network manager.