Text 4 to answer question.

Enterprise-class firewalls, such as those made by FORTINET, Cisco Systems and NetScreen Technologies, have long been marketplace commodities. Out of the box, they provide reliable, relatively easy-to-use security solutions. Buying some licenses from vendors can also provide 24/7 support and ongoing maintenance. In addition, commercial firewalls have configuration facilities, usually through graphical interfaces, and facilitated interaction with other security technologies such as SIEM, EDR, DRP, etc.

But commercial firewalls have a problem: many would say that they are expensive. That is why some IT teams consider the use of other options like open-source firewalls. iptables®, for example, is a freeware Linux tool developed by NetFilter that isn’t nearly as easy to use, but it’s quickly catching up in features and functionality.

iptables® firewall boasts many features normally found only in commercial firewalls, including packet defragmentation, rate limiting, integration of VPNs, scale up and scale down, packet content inspection and protocol state tracking.

So why don't we always use iptables® firewall instead of proprietary applications or devices? In addition to the support from manufacturers that the more traditional choice has, we can highlight iptables’® need for professional training, and also the need for hiring large support teams, which could cost even more money in some scenarios.

Disponível em:< https://searchsecurity.techtarget.com/opinion/Commercialfirewalls- vs-Open-source-firewalls>. Acesso em 20 mar. 2021, com adaptações