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    PfSense and direct attached cable modem

    Scheduled Pinned Locked Moved General pfSense Questions
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    • S
      sammy2ooo
      last edited by

      Is it possible to directly connect my cable modem to the router? If configure the wan interface for dhcp it never gets an address or response from the modem… If I got it right the modem retrieves its ip from the ISP and the cable modem needs to get bridged to the wan interface... what am I missing here?

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      • chpalmerC
        chpalmer
        last edited by

        Connect everything together
        Try rebooting your cable modem first then reboot pfSense.

        Triggering snowflakes one by one..
        Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

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        • S
          sammy2ooo
          last edited by

          tried that before with no luck. So there is no special configuration needed for this setup? Simply setting the WAN interface to DHCP should do the trick?

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          • Cry HavokC
            Cry Havok
            last edited by

            Yes, that is all that should be required - what ISP are you with and what settings do they recommend for Windows?

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            • S
              sammy2ooo
              last edited by

              i am with cablecom. My modem is currently connected to linksys WRT54GL router running OpenWRT. The MTU is set to 1500. What exactly do you mean by "what do they recommend for windows", the MTU?

              eth0.1    Link encap:Ethernet  HWaddr 00:18:F8:5F:xx:xx 
                        inet addr:84.74.xxx.xxx  Bcast:255.255.255.255  Mask:255.255.240.0
                        UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
                        RX packets:35265875 errors:0 dropped:0 overruns:0 frame:0
                        TX packets:17045557 errors:0 dropped:0 overruns:0 carrier:0
                        collisions:0 txqueuelen:0
                        RX bytes:818423469 (780.5 MiB)  TX bytes:1751394547 (1.6 GiB)

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              • Cry HavokC
                Cry Havok
                last edited by

                If it works with OpenWRT, there's no reason it won't work with pfSense, assuming you use the same basic configuration.

                What you may have to do is have the OpenWRT host release the DHCP lease, power it down, plug in the pfSense host and then power it up.

                Alternatively, try cloning the MAC address of the OpenWRT host to the pfSense host.

                The question about "what they recommend for Windows" was about the general network config, if they recommended any non-default settings it would have pointed to a need to apply custom settings.  However, if you've got OpenWRT working, there's obviously nothing special needed.

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                • S
                  sammy2ooo
                  last edited by

                  Okay, I'll give that a try when I am back in front of the router hardware…
                  But I have still some questions about this constellation: that means the cable modem acts on the ISP-side as a DHCP client and on the customer side as an DHCP server, is that correct? Is there no bridging taking place? Thanks for your help!

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                  • chpalmerC
                    chpalmer
                    last edited by

                    Unless you have a "all in one type" like this the cable modem is simply a bridge.

                    Your ISP's DHCP server is on their premises.  They will hand your modem an IP but its for their use…

                    Triggering snowflakes one by one..
                    Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

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                    • S
                      sammy2ooo
                      last edited by

                      Well okay, so I assume its a simple bridge. But why do I need to configure the WAN interface for DHCP? The cable modem already got its ip and the WAN interface only needs to get bridged?  That means the router wan interface simple shouldnt care about anything ip-related stuff ???

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                      • Cry HavokC
                        Cry Havok
                        last edited by

                        Ah, you misunderstand - the cable modem is acting as a bridge between you and the ISP (while they share the same physical medium, the cable modem is usually on it's own logical network).

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                        • S
                          sammy2ooo
                          last edited by

                          Okay, now I got it… The routers WAN interface retrieves its public IP directly from the ISP not from the cable modem... roger that :-) Thanks for your patience

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                          • chpalmerC
                            chpalmer
                            last edited by

                            Yep!

                            Heres a good over detailed explanation in case your curious…    ;D

                            http://www.usr.com/support/6000/6000-ug/two.html

                            Triggering snowflakes one by one..
                            Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

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