What is a Firewall?
Firewalls and proxy servers play a crucial role in network security by providing the first line of defense against cyber threats, making them an essential part of any cybersecurity strategy. Whether you're an ethical hacker or a cybersecurity professional, understanding how these systems work will be crucial.
A firewall is a network security device that monitors and filters incoming and outgoing network traffic based on an organization's previously established security policies. At its most basic, a firewall is essentially a barrier to keep destructive forces away from your property. In fact, that's why its called a firewall. Its job is similar to a physical firewall that keeps a fire from spreading from one area to the next.
Firewalls guard traffic at a computer's entry point called ports, which is where information is exchanged with external devices. For instance, "Source address 172.18.1.1 is allowed to reach destination 172.18.2.1 over port 22."
Firewalls can provide different types of protections, but the main ones are:
- Packet filtering: This method inspects packets of data traveling to or from a network. It compares the packets to a set of established criteria like allowed IP addresses and packet type. If the packets don't meet the criteria, the firewall stops them.
- Stateful inspection: Also known as dynamic packet filtering, this method monitors active connections and uses the information to determine which network packets to allow.
- Proxy service: In this method, the firewall intercepts and inspects packets, then forwards them if they meet the criteria. This method effectively hides the true network addresses.
What is a Proxy Server?
A proxy server acts as an intermediary or middleman between a user and the websites they browse. They can be set up as a firewall or a web filter, acting as a layer of cybersecurity that prevents cyber attackers from entering a private network and protects your computer against malware and other cyber threats.
When an individual uses a browser, they normally communicate directly with the internet, but with a proxy server, the proxy communicates with the internet on their behalf. When someone uses a proxy server, the internet traffic goes through the proxy before reaching the destination computer. Since all communication is happening through the proxy, it offers some level of security and privacy, and a number of IT companies depend on proxy servers to filter out any potentially harmful data that might come in from the internet.
The main reasons why proxy servers are used include:
- Filtering incoming traffic, making the company’s network more secure
- Keeping the company’s network more private
- Speeding up access to resources through the use of a cache
Firewall vs Proxy Server
While both firewalls and proxy servers provide network security, they do so in different ways and offer different capabilities. A firewall primarily focuses on blocking harmful or unauthorized network traffic, which is crucial for preventing cyberattacks. A proxy server, on the other hand, focuses on masking and manipulating network traffic, which provides privacy and the ability to bypass network restrictions.
In the context of ethical hacking and cybersecurity, understanding how firewalls and proxy servers work is crucial. Ethical hackers often need to bypass these systems to test their security, while cybersecurity professionals need to understand how to properly configure these systems to provide maximum security.