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    Using PfSense to serve CGNAT or Dual Stack Lite

    Scheduled Pinned Locked Moved Routing and Multi WAN
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    • 0daymaster0
      0daymaster
      last edited by

      Hi. I am launching a WISP as we speak and I only have a limited IPv4 block from my upstream service provider. I'm looking to put my CPE gateways behind a CGNAT and using pfSense as a combined edge router, firewall and NAT box. Running CGNAT should be as simple as assigned a 100.64.0.0/10 subnet to an interface. My question is how to implement RFC7422 (fixed port ranges for each customer device). Or is there any way to implement Dual Stack Lite on pfSense? Thanks.

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      • johnpozJ
        johnpoz LAYER 8 Global Moderator
        last edited by

        @0daymaster said in Using PfSense to serve CGNAT or Dual Stack Lite:

        RFC7422

        Very important info from that rfc.
        "The RFC Editor has chosen to publish this document at its discretion and makes no statement about its value for implementation or deployment."

        So are you are wanting to do this for the logging aspects of this? I don't see how this helps you to be honest, since you would need more IPs and Ports when customer exceeds their sessions that you have broken out to them.

        There is no such capability that I am aware of it pfsense or freebsd that could do this without large amount of manual setup.

        You could manually create the outbound nats to only use specific ports for translation, and setup them to use a specific VIP/Interface on the public side.

        portrange.png

        But not sure what happens when say you give 5000 ports to customer X and they need 5001+

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        • 0daymaster0
          0daymaster
          last edited by 0daymaster

          Thanks. Yes, I want to implement this for legal reasons. By assigning ranges of ports to CPE devices I would not have to run DPI in order to track outbound connections. I will ask our upstream service provider for best practices on running CGNAT as they were the ones who suggested it.

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          • 0daymaster0
            0daymaster
            last edited by 0daymaster

            @johnpoz According to Juniper 1024 ports is a liberal assignment for 250+ NAT sessions. From my experience as an MSP most customers will never exceed 1500 NAT sessions (unless they torrent) so ~5000 ports is actually a pretty good number.

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            • johnpozJ
              johnpoz LAYER 8 Global Moderator
              last edited by

              So your customer is a single family home.. Not a business with 50 users?

              An intelligent man is sometimes forced to be drunk to spend time with his fools
              If you get confused: Listen to the Music Play
              Please don't Chat/PM me for help, unless mod related
              SG-4860 24.11 | Lab VMs 2.8, 24.11

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              • 0daymaster0
                0daymaster @johnpoz
                last edited by

                @johnpoz Mostly small businesses.

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                • 0daymaster0
                  0daymaster
                  last edited by

                  My immediate goal in regards to addressing is to make it long enough so that I can purchase a class C IPv4 netblock on the open market. Nothing would make me happier than the death of IPv4 but until then I am forced to support it.

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