Firewall, traditional and next-generation network security


A firewall is a network security device, a piece of software, or both, which monitors both incoming and outgoing network traffic in order to block a specific type of traffic based on a defined set of security rules.

Usually categorized as network or host-based firewalls, these systems, that can be a hardware device, software, or both, basically create a barrier between a trusted local network and untrusted outside/public network, like the Internet.

There are several types of firewalls ranging from early types that include a proxy firewall, stateful inspection firewall, and unified threat management (UTM) firewall, to more modern types like next-generation firewalls (NGFW).

Proxy firewalls were one of the first devices that served as a gateway from one network to another, while the so-called “stateful inspection” firewalls, which are now considered as a traditional firewall, allow or block network traffic based on state, port and protocol.

Unified threat management firewall usually combines a network firewall with further security functions like anti-virus, anti-spyware, anti-spam, content filtering, intrusion detection and prevention systems, as well as remote routing, network address translation (NAT) and virtual private network (VPN) support from

According to Gartner, next-generation firewalls (NGFW) are deep-packet inspection firewalls that include standard firewall capabilities like port/protocol inspection and blocking but also include application awareness and control, integrated intrusion prevention, sandboxing as well as techniques that address evolving security threats.An NGFW should not be compared to a stand-alone network intrusion prevention system (IPS), which includes some functions of the firewall but is not as closely integrated.

Some network companies, like Cisco, developed threat-focused NGFW, which provide advanced threat detection and protection.

Future of firewall, software- and cloud-based alternatives

What made the next-generation firewalls (NGFW) interesting to enterprises/businesses and/or network security administrators is the fact that you can replace a lot of security devices, including IDS/IPS, web-security and SSL decryption gateways, network proxies and others, with a single tightly integrated NGFW, eliminating network complexity.

Of course, such consolidation also came with a big drawback in terms of network functionality, its performance as well as a lack of certain features and general limitations.

Cloud-computing and software is evolving the network and network security has to follow with many of the well-known network security companies pushing toward software-based micro-segmentation network security tools, like the Cisco Application Centric Infrastructure (ACI) or Vmware’s NXS Network Virtualization and Security Platform. There is also a big focus on cloud-services with SaaS provider that can effectively replace NGFW for certain customers.

Of course, next-generation firewalls (NGFW) won’t be gone overnight and there is still a market for a traditional firewall hardware but the network, as well as the network security, is constantly evolving in order to meet with demands and security threats.


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Slobodan Simic is foremost an IT enthusiast who discovered his knack for writing, which lead to becoming both an IT journalist and later an Editor for a number of publications. He has been covering anything from the consumer- and professional-oriented hardware to software markets and networks. With a focus on chasing down leads, making sure that fresh content is ready for publishing, as well as keeping up with the evergrowing and evolving IT world, writing has become more of his passion rather than just a job.