Both of them limit or block connections to or from a network, but they do so in a very different way. While firewalls block communications (ports or unauthorized programs that try to access a network without authorization) proxies simply redirect them.

But…What exactly is a proxy?

A proxy is a program or a device that protects and improves access to a site. To do so, it creates a barrier between the local network and the Internet and, therefore, avoid direct communications between the client and the server, so that no external user can see the network (only the IP of the proxy server will be visible).

How does it work?

When users access the Internet through a proxy, they launch a request. The proxy receives that request and sees if it is already stored in its cache. If it is not, the proxy will be the one that accesses the Internet and delivers the information to the user (this requires a previous configuration of the browser in which the IP and port of the proxy are indicated).

Popular use cases of proxies:
  • Access to services whose content is blocked for a specific country
  • Private and anonymous Internet Access  (cookies, scripts and so on can be blocked)
  • Knowledge about internet usage among employees
  • IP hiding (with malicious purposes)
  • Filtering tool: so that those requests considered inappropriate or to which the user does not have access, are not answered (it is important to highlight that when a proxy blocks a site, it does not block the communication but redirects the request)
  • Improvement of the network performance thanks to its cache

And…a firewall?

A Firewall is an application (or hardware device) that protects a local network or device by blocking or allowing communications from the outside (Internet) to the device or network.

How does it work?

The administrator sets the rules that will define how the firewall behaves when a package that meets certain criteria is received (it can block game programs, instant messaging applications, or whatever).

Both concepts can be combined perfectly. An example of this would be the integration of a filtering proxy with a firewall, so that the firewall can block or allow access according to the categories previously established in the proxy

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