What is a Firewall and How Does it Work?

With advancements in technology today comes enhanced risk for security breaches and cyber attacks. Firewall protection is security measure used to evaluate your network traffic to ensure your network and data stay secure. Read on to learn more about what a firewall is, how it works, and how it can protect your business. 

What is a Firewall?

The term “firewall” originally referred to an actual wall that was built to protect structural architecture from fires, especially in populated areas where structures were built in conjoining rows. The firewall was a solid structure of block or sheet of metal that prevented the fire from moving through buildings to the surrounding structures. The computing industry, while in its infancy, borrowed the term and applied it to network computing to protect the internal networks from outside threats.

 

Network Firewalls

Firewalls are part of the network security system that filters incoming and outgoing network traffic based on the network security rules defined by system users. The primary purpose of the firewall is to reduce or eliminate unwanted network communication and malicious attacks. The firewall acts as a barrier to keep these destructive elements out of the internal network and can be hardware, software, or a combination of both.

Hardware Firewalls

Hardware firewalls are physical components built into the network devices (such as routers) and serve to protect a single computer or a network. Hardware firewalls require little configuration post manufacturing to work effectively with the internal network. They work by filtering packets of data from their sources to their destinations and reconcile the packets with the predefined security rules.

Software Firewalls

Software firewalls are popular solutions for small companies and user machines. Software firewalls can come as an application or be a part of an anti-virus or security software suite. Software firewalls work to protect incoming and outgoing network traffic as well protect systems against Worms and Trojans. Often, businesses deploy both hardware and software firewalls for added layers of protection.

How Does a Firewall Work?

Firewall protection monitors all incoming and outgoing network traffic to determine “good data” versus “bad data” through three methods.

Packet Filtering

Packet filtering is the most basic form of firewall protection that evaluates data traffic against predefined security rules to create filers. Data travels in packets on the open Internet and when it reaches its destination at an organization’s network the data packet header is stopped at the firewall. The firewall evaluates the data, and either drops it or allows the data packets associated with the header to move through into the internal network.

Proxy Server

A firewall proxy server is an application that acts as an intermediary between two end systems, the external Internet server and the internal servers within the organization. This type of firewall protection does not allow the two servers to communicate directly and works on the application levels of the session protocol, known as Layer 7. They operate by emulating the two servers as if they were communicating and evaluate the health and fitness of such communication as if the two servers were speaking directly. Almost all modern-day firewalls now include a proxy server.

Stateful Inspection

Stateful inspection is the most modern method of firewall protection as well as the most efficient because it does not rely on memory-intensive examination of all data packets. Instead, the stateful firewall collects and hold attributes of both connections in a database of trusted information during the communication; thus, giving rise to the name “state” for the state of the connection. Information that is collected for the stateful inspection includes all available details of the IP addresses and ports used in the connection. Like the proxy server, stateful inspection firewall configurations also work on the application level.

What is a SIP Aware Firewall?

Communication and cloud services today are more complex than other IP data traffic. Other factors also play a major role in VoIP communication, such as the quality of service. With reputation and business services on the line, your company cannot afford to experience a data breach, but at the same time, your business cannot afford to lose out on a missed communication that gets blocked at the firewall. That is why SIP awareness at the firewall is so important. Having a SIP-aware firewall allows for safe and secure VoIP communication through the firewall.

Many unified communication service partners offer solutions and additional services to help you configure the best system to protect all your Internet communications. Firewalls have evolved significantly since the early 1980s routers, and while some organizations choose to deploy session border controllers instead of firewalls, your cloud service partner can help you develop a system that works for your company.

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