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Basic Networking Question

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  • Basic Networking Question


    I feel stupid asking this question but I can't seem to wrap my head around this one. I recently inherited a network and I am wanting to replace the firewall. I have always worked on networks that use NAT, ie. computers on the LAN all have unroutable private IPs that are translated to the routable WAN IP on the router. On my new network all internal IPs are routable IPs. When I go to the LAN IP of my computer shows up. How does this work? What is this called so I can learn more about it?

  • #2
    Re: Basic Networking Question

    It's not really called anything. It's just a network that doesn't use RFC1918 addresses and doesn't use NAT. There's nothing inherently wrong with this as prior to RFC1918 everyone used routable addresses internally. It's a little unorthodox to see a network like this these days but there's nothing wrong with it. You probably could configure NAT if you want but the more important thing is to make sure that your firewall is set up correctly regarding inbound traffic.

    I've been managing a network with routable addresses internally for 5 years with no ill effects.


    • #3
      Re: Basic Networking Question

      Thanks joeqwrty! I am the LAN admin for a faculty at a large university and what I have is a subnetted class B network. We currently run an OpenBSD firewall and I want to replace it with an Untangle device or a Fortinet firewall. I'm just not sure how to set either of these up without NAT.


      • #4
        Re: Basic Networking Question

        Route the traffic instead of using NAT.
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