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How to turn your Firewall concepts from zero to hero


How to turn your Firewall concepts from zero to hero

A firewall is one such solution that prevents unauthorised access to our computer systems and data. Now a days, protecting our sensitive data from unauthorised and unwanted sources is a major concern.

A firewall is one such solution that prevents unauthorised access to our computer systems and data. Now a days, protecting our sensitive data from unauthorised and unwanted sources is a major concern.

We will discuss in this article the fundamentals of firewalls, such as their necessity, uses, drawbacks, and different types. Firewalls are mostly used by system administrators, system engineers, network engineers, and network administrators because they have to handle the configuration, troubleshooting, and monitoring of firewalls.

What exactly is Firewall?

A firewall is a computer system or network component that allows authorised communications while preventing unauthorised access. Firewalls are still widely used and have had a significant effect on current security practises.

Software, hardware, or a hybrid of the two can be used to implement firewalls. Unauthorized internet users are frequently prevented from accessing private networks linked to the internet by firewalls, particularly intranets. Every message entering or leaving the intranet must travel through the firewall, which inspects each one and rejects any that do not adhere to established security requirements.

Firewall working

A firewall system analyses network traffic using pre-established rules. Following that, it filters the traffic to stop any of that traffic from originating from unreliable or illegal sources. Only inbound traffic that has been set to accept is allowed.

Firewalls utilise the following three methods to control traffic entering and exiting a network:

  • Packet filtering
  • Proxy services
  • Stateful packet inspection
  • Packet filtering

    Packet filtering is one of the important services provided by firewalls. Packets are small data chunks that are inspected as they pass through the network using user-defined packet filtering rules.

    Packets are permitted or denied based on a wide range of criteria:

  • Source address
  • Source port
  • Destination address
  • Destination port
  • Protocols(IP, TCP, ICMP, etc.)
  • Proxy services

    A proxy server basically works as a middle-man for communication between devices. A Proxy server intercepts each message coming into and going out of the network. The true network addresses are effectively masked by the proxy server.

    Proxy servers have long been used to store a local copy of the requested external data. This enhanced performance in circumstances with inadequate bandwidth by enabling clients to request data through the proxy rather than the real external source.

  • Source address
  • Source port
  • Destination address
  • Destination port
  • Protocols(IP, TCP, ICMP, etc.)
  • Stateful packet inspection

    For the duration of the session, a “stateful” firewall stores key characteristics of each connection in a trusted information database. Monitoring TCP or UDP sessions between devices allows stateful packet inspection to provide services beyond simple packet filtering.

    Stateful inspection allows for the tracking of connections coming from a trusted network. A state session table that stores this session information enables temporary firewall openings for return traffic that would otherwise be blocked.

    To stop Denial of Service (DoS) attacks, connections from the untrusted network to the trusted network are carefully watched.

    Firewall types

    Firewalls are of two types:

  • Software firewalls – For home users, software firewalls are the most common type of network protection. They typically come as standalone programmers or a component of comprehensive anti - virus protection software. A software firewall can guard against trojan or worm applications in addition security for both inbound and outbound traffic
  • Hardware firewalls – Every machine on a network can be protected by hardware firewalls, which are incorporated into networking equipment like routers and need minimal configuration to function. They check a packet’s header using packet filtering techniques to ascertain its source and destination.
  • Uses of firewall

    The client-server concept, which forms the basis for network security in modern computing, originated from firewalls. To examine traffic and reduce dangers, the majority of devices rely on firewalls or technologies that are quite similar to them.

  • Prevents the delivery of malicious content as well as unauthorised remote access.
  • A firewall can filter traffic and notify the user of intrusions on a single home network.
  • At home networks, static IP addresses are used; they are particularly helpful for always - on connections like cable modems and digital subscriber line(DSL) connections.
  • Network address translation(NAT), a sort of firewall, efficiently protects systems from people who are outside the connection to which they belong.
  • Drawbacks of firewall

    Everyone thinks that firewalls are powerful enough to protect our computer systems or networks from online threats. However, “firewall is not very powerful”. Therefore, it’s crucial to employ additional defence mechanisms to assist in safeguarding the network and computer data. Cyber threats are dynamic in nature, a firewall should not be the only component considered while securing the home network.

  • Firewalls are unable to stop the distribution of software or files that are compromised with viruses.
  • Black hat hackers using modems cannot be stopped by firewalls from dialling into or out of an internal network.
  • Firewalls cannot protect already hacked systems.
  • Inaccurately setup security policies will not be secured by firewalls.
  • Firewalls are unable to defend against social engineering and other non - technical security concerns.
  • Certifications availables for firewall

    Certifications play an important role for those who are already working as professional network engineers or with similar designations in networking domains. Several certifications are available on the market, but only a few provide the necessary skills and knowledge.

    The Palo Alto and Fortinet Fortigate certifications are highly recommended for qualified Cisco engineers or professional network engineers. Both the certifications do not require any experience or certifications, but they recommend having basic knowledge of networking and cyber threats.

    Core firewall principles like routing, VPN, user authentication, and firewall policies are covered by these certifications. Students will get knowledge about web filters and efficient application control to secure their users.


    Firewalls are an essential part of network security; anyone interested in learning about the setup and administration of firewalls, or those who are newbies in network security and want to advance their skill set, can choose this route.

    So in this blog, we have provided an overview of firewall use, types, functions, and limitations. At Networkers Home, we provide both certifications and training for highly qualified Cisco engineers or individuals who want to learn and excel as professionals in firewall.

    Keep learning, keep exploring!


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