I'm wondering, if I enable access to an internal web server through my home router / firewall via port forwarding. Which firewall architecture corresponds to this setup?

Screened Host, Screened subnet, or Dual Homest Host?

To me, Screened host makes most sense. But I vaguely remember our teacher saying it was the Screened Subnet architecture. However, I doubt that as the screened subnet architecture uses 2 firewalls. Any thoughts?

  • Does your home router have a dedicated interface for that host or is everything connected to the internal switch? Typically a home router with a dedicated DMZ interface is a multi-leged/collapsed firewall with a screened subnet. If there is only one host in that subnet it's also a screened host. If you have only one interface it is none of the named topologies. (Besides the concepts are not well defined and pretty old fashioned anyway)) – eckes May 20 '17 at 11:43

Look at this wonderful documentation.

Your scheme is not one of the three you said because I guess between your server and your other internal machines there is no firewall between them. So, your topology is very simple and is Screening router corresponding to this picture:


As they explain there, your topology is the cheapest (and least secure) setup. Anyway is very normal to have this at home.

  • That picture makes it impossible to see how many networks and network interfaces are involved. – eckes May 20 '17 at 11:19
  • It doesn't care. Is a scheme to understand concepts. Is enough to answer question. – OscarAkaElvis May 20 '17 at 11:33
  • No it does not, the screened server could be a router or in the internal subnet, in both cases it would not be a screened server. – eckes May 20 '17 at 11:35
  • Is your opinion. Mine is explainning perfectly what OP wants to know. Of course the possibilities and combinations are infinite but we don't have infinite space to write all of them. I think the answers must be synthesized like this. I think you should create your own answers. – OscarAkaElvis May 21 '17 at 7:02

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