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    Cablem Modem Access - Behind Pfsense

    Scheduled Pinned Locked Moved General pfSense Questions
    32 Posts 11 Posters 27.0k Views
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    • johnpozJ
      johnpoz LAYER 8 Global Moderator
      last edited by

      you really shouldn't have to do anything here.  I access my cable modem on 192.168.100.1 without doing anything in pfsense at all.  It gets a public IP 24.13.x.x and I have no issues accessing my cable modem interface..  Works out of the box.

      While it shouldn't matter the only rule I have disabled is the block rfc1918 and bogon on the wan because I see no point to them, they do nothing in the real world since networks they block don't route on the internet anyway.  And I have my port forwards open to the planet so what is the point in having a rule to block something that doesn't even route ;)

      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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      • chpalmerC
        chpalmer
        last edited by

        What is your LAN subnet and what do your LAN firewall rules look like?  Screenshots would be wonderful.

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

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        • chpalmerC
          chpalmer
          last edited by

          My guess is one of these issues-

          Your LAN is 192.168.100.0/x

          You have built LAN rules that block your LAN from accessing 192.168.100.1 (maybe without realizing it..)

          This modem is rented and your ISP has turned off the the GUI (which you have already disproved)

          If 192.168.100.1 is outside your LAN subnet you will have no problem reaching it by default. If it is inside your LAN subnet it will be unreachable as your client machines wont even pass the request to your pfSense box but instead try and find it locally.

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

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          • G
            ghkrauss
            last edited by

            Here are screen shots of the current firewall rules. The cable modem is my own hardware. The GUI for the cable mode is operational if I make a direct connection with a notebook computer (no firewall).

            Capture1.PNG
            Capture1.PNG_thumb
            Capture2.PNG
            Capture2.PNG_thumb

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            • jahonixJ
              jahonix
              last edited by

              You block RFC1918 networks on WAN. 192.168.x.y is one of those private RFC1918 networks.
              At  Interfaces | WAN  you should uncheck "Block private networks".

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              • C
                cmb
                last edited by

                @jahonix:

                You block RFC1918 networks on WAN. 192.168.x.y is one of those private RFC1918 networks.
                At  Interfaces | WAN  you should uncheck "Block private networks".

                That's only for ingress traffic. Reaching the modem is egress. Don't change that, it's fine as-is.

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                • jahonixJ
                  jahonix
                  last edited by

                  Sure and I would think so too.
                  I have a VDSL modem in router mode (…don't ask) with an RFC1918 IP on WAN of my pfSense and I had to explicitly uncheck this to get modem access working.
                  Don't know why this solved it this way but I had to get VoIP working first and didn't care about it later.

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                  • M
                    macboy6
                    last edited by

                    I can access my cable modem IP of 192.168.100.1 with 0 changes to pfsense config.  It just works.

                    Make sure you have a firewall rule on your LAN interface that allows you to reach any destination IP address.  If you are restricting access from LAN interface to RFC1918 addresses, then you will have to have a rule above it that allows you to reach destination 192.168.100.1.

                    No reason why this shouldn't work.

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                    • chpalmerC
                      chpalmer
                      last edited by

                      @chpalmer:

                      What is your LAN subnet  ?

                      Please!  ;)

                      Here are screen shots of the current firewall rules. The cable modem is my own hardware. The GUI for the cable mode is operational if I make a direct connection with a notebook computer (no firewall).

                      Can you also post what your firewall logs say when you try to connect?  Is there anything there that would indicate a block?  (my guess is you will see nothing there.)

                      Try from your desktop-  c:/>ping 192.168.100.1

                      Try from your pfsense box..  /diagnostic/ping  192.168.100.1

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

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                      • G
                        ghkrauss
                        last edited by

                        Thanks  for all the help in trying to understand the issue. I checked the firewall log after multiple attempts to access 192.168.100.1 (no entry). I noticed that the browser (firefox) shows https://192.168.100.1. Interesting it is https. The ip traffic passes through the firewall via the ping process. I have attached a screen capture. Could the issue be some sort of dns problem? The LAN subnet is 192.168.1.0, 255.255.255.0

                        Capture3.PNG
                        Capture3.PNG_thumb
                        ![Capture 4.PNG](/public/imported_attachments/1/Capture 4.PNG)
                        ![Capture 4.PNG_thumb](/public/imported_attachments/1/Capture 4.PNG_thumb)

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                        • johnpozJ
                          johnpoz LAYER 8 Global Moderator
                          last edited by

                          so clearly you can ping it.. So are you running a proxy.. That could cause you issues, or captive portal?

                          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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                          • G
                            ghkrauss
                            last edited by

                            No proxy running on the firewall or elsewhere. The web browsers on the workstation are direct connect ie. no proxy. I am trying to examine everything to figure out what's in the world is causing the issue. Thanks for your suggestions. I am just going to continue until the source is discovered!

                            Best,

                            Howard

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                            • johnpozJ
                              johnpoz LAYER 8 Global Moderator
                              last edited by

                              what I would do is sniff on your wan.. You see the request going out to 192.168.100.1 - what do you get back if anything?  Makes no sense that if you can ping it, and its has a gui that is there that you would not be able to access it.

                              You don't have any floating rules do you?  Some people that have really tight tinfoil hats like to lock down on outbound anything to rfc1918.. There been some threads about it, Its also a way to make sure you don't leak noise packets.  So it can be a good thing… I tried it for a while, but when I got no hits on it ever.  I wasn't leaking rfc1918 out to the internet I saw no use of it - and yeah it prevented me from talking to my modem.

                              See attached, where the rfc1918 float rule is disabled.  But I do still have my anti noise netbios rule.  Window machines has a nasty habit of doing a directed query to even public IPs via netbios..  Just no reason to let that out just trying to be a good netizen and keep my network from adding to the noise of the internet.

                              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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                              • H
                                highwire
                                last edited by

                                With my Motorla SB6120, I could access the GUI on 192.168.100.1 with no changes to pfSense.  With my Cisco DPC3848, I cannot (though I can still ping it).  I believe that a lot of modems will allow any source IP address to connect (netmask 0.0.0.0) while others require the source IP address to be in the same subnet (192.168.100.0/24).

                                Below is how I got it working.  Create a virtual IP (I use 192.168.100.2), and then create an outbount NAT rule to translate your computer's IP address to 192.168.100.2 when accessing 192.168.100.1 so that your modem won't ignore it.  I had to reboot the pfSense firewall after doing this for it to take effect.

                                1. Firewall -> Virtual IPs
                                • Type: IP Alias
                                • Interface: WAN
                                • Address Type: Single address
                                • Address: 192.168.100.2 (if your modem's GUI is on 192.168.100.1)
                                • VHID Group: 1
                                • Advertising frequency: Base - 1, Skew - 0
                                1. Firewall -> NAT -> Outbound
                                • choose "Hybrid Outbound NAT rule generation
                                • Add a new rule:
                                  a) Interface: WAN
                                  b) Protocol: Any
                                  c) Source: Any
                                  d) Destination: Type - Network
                                  e) Destination network for the outbound NAT mapping: 192.168.100.1/32
                                  f) Translation: Address - 192.168..100.2()
                                  g) Description: "Cable modem access"
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                                • G
                                  ghkrauss
                                  last edited by

                                  What port did you specify in the Firewall Outbound setup?

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                                  • H
                                    highwire
                                    last edited by

                                    I left all the ports blank ('all ports').

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                                    • chpalmerC
                                      chpalmer
                                      last edited by

                                      What is the absolute error on your browser when you try?  HTTPS might just be a certificate error and refusal to connect.

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

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                                      • G
                                        ghkrauss
                                        last edited by

                                        No certificate error. But just wondered if htts might be an issue. I am still working on this today to see if I can make any progress.  It may be just some issue with the Netgear CM 500 cable modem. I had an older Arris SB 6141 cable modem and had absolutely no issue. If these firm could just have a "engineering standards approach there would be less issues!

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                                        • W
                                          wbond
                                          last edited by

                                          Have you tried forcing http?  I can reach my cable modem with http://192.168.100.1, but not https://192.168.100.1.

                                          *update: Mine is a Netgear CM600.

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                                          • G
                                            ghkrauss
                                            last edited by

                                            Thanks for tip. I tried it and it started to connect but then just stalled after I put in the user and password. I then tried to repeat the process and no connection was available. Some strange process…

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