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    How to stop free DNS

    Scheduled Pinned Locked Moved NAT
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    • S
      surajitom
      last edited by

      We are using pfSense 2.3.3. We have configured NAT and forwarding all the traffic towards the Open DNS. Rule is working fine. I have made aliases, where I am trying to store  all the free DNS. When my user is using free DNs and if it’s matched to my aliases, the content is being blocked. Every single day someone able to find out a new free DNS from the web and they are able to bypass the firewall rules and becoming nightmare for me. I have stored some around 350 free DNS, and I am able to find out that it’s a tedious and meaningless job. Now it’s my humble request to all of you is that thus it possible that whatever the DNS my user is using ,if it’s  match to my pfSense DNS server, then only user could able to access the internet ,otherwise not.
      Thanks in advance.
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      ![nat 6.png](/public/imported_attachments/1/nat 6.png)
      ![nat 6.png_thumb](/public/imported_attachments/1/nat 6.png_thumb)

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      • johnpozJ
        johnpoz LAYER 8 Global Moderator
        last edited by

        Whack a mole is not best way to do anything.  If you do not want people to use other than your own, etc.. Just block all dns and only allow the dns you want to use - this would be a much shorter list ;)

        Its hard to understand your rule list without seeing the full picture.. Just allow dns to your pfsense, anything else dest to 53 just redirect..  No need to create the open alias at all.

        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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        • GruensFroeschliG
          GruensFroeschli
          last edited by

          If i dont want users to use their own DNS server, i do this:
          https://doc.pfsense.org/index.php/Redirecting_all_DNS_Requests_to_pfSense

          We do what we must, because we can.

          Asking questions the smart way: http://www.catb.org/esr/faqs/smart-questions.html

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          • NogBadTheBadN
            NogBadTheBad
            last edited by

            @johnpoz:

            Whack a mole is not best way to do anything.  If you do not want people to use other than your own, etc.. Just block all dns and only allow the dns you want to use - this would be a much shorter list ;)

            Harder to do in some cases, my Netflix client on my "Smart" TV always uses 8.8.8.8 for DNS regardless of what is set on the TV ;)

            If I was that worried I'l use the method GruensFroeschli posted.

            Andy

            1 x Netgate SG-4860 - 3 x Linksys LGS308P - 1 x Aruba InstantOn AP22

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            • johnpozJ
              johnpoz LAYER 8 Global Moderator
              last edited by

              True if something has dns hard coded and you don't want it to use that dns, then yes you have to hijack/redirect it per the link GruensFroeschli provided.. Which is not whack a mole like the OP is attempting..

              From the rules I can see I don't even see his reason for the whack a mole alias.. From the rules I can see if user picked something that was not in the alias it would be blocked.. So why not just use 1 rule redirect all to 53 and be done with it..

              "Every single day someone able to find out a new free DNS from the web and they are able to bypass the firewall rules"

              He says users are able to bypass?  So he must have a any any rule in there somewhere above his access to lan for dns and his block?  Really need to see his full rules list to figure out how his users are able to bypass.

              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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              • GrimsonG
                Grimson Banned
                last edited by

                Have a look at his earlier thread concerning this: https://forum.pfsense.org/index.php?topic=140777.0

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