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    Completely confused by DNS failure (dnsmasq)

    Scheduled Pinned Locked Moved DHCP and DNS
    dnsdnsmasq
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    • N
      NickJH
      last edited by NickJH

      pfSense is natting. I didn't include the dump of the packets at the pfSense external interface but they match the packets coming back from the Firewall.

      Also external resolution works in the PC.

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      • S
        SteveITS Galactic Empire @NickJH
        last edited by

        @NickJH Then it should "just work." DNS Forwarder is really old though...you can set DNS Resolver to forward via a checkbox, though uncheck the DNSSEC checkbox if you do.

        Pre-2.7.2/23.09: Only install packages for your version, or risk breaking it. Select your branch in System/Update/Update Settings.
        When upgrading, allow 10-15 minutes to restart, or more depending on packages and device speed.
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        • N
          NickJH
          last edited by

          That is the problem. It doesn't work and I have no idea why. It correctly gets a response back from the Firewall when querying external DNS.

          I can't use a recursive resolver unless I replicate all the hosts that are in the Firewall for my split DNS. That would be a pain. For that reason I switched to a forwarder temporarily.

          Alternatively, can I bulk load hosts into pfSense?

          I am now just trying to switch the resolver to forwarding as you suggest.

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          • johnpozJ
            johnpoz LAYER 8 Global Moderator @NickJH
            last edited by johnpoz

            @NickJH said in Completely confused by DNS failure (dnsmasq):

            response packets at the pfSense WAN interface.

            But what response - what should it respond with for sia2.howitts.co.uk?

            I don't see A response.. A response would look like this.

                192.168.9.100.49907 > 192.168.9.253.53: 64979+ [1au] A? nas.home.arpa. (54)
                192.168.9.253.53 > 192.168.9.100.49907: 64979* 1/0/1 nas.home.arpa. A 192.168.9.10 (58)
            

            This is not a valid response
            15:59:39.895289 IP 192.168.1.1.53 > 192.168.1.4.63611: 2* 0/0/0 (36)

            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 2.7.2, 24.11

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            • S
              SteveITS Galactic Empire @NickJH
              last edited by

              @NickJH The "Enable Forwarding Mode" forwards anything that isn't a host or domain override.

              @NickJH said in Completely confused by DNS failure (dnsmasq):

              can I bulk load hosts into pfSense?

              I don't think so but you can put it in the config file and then restore just the DNS Resolver config.

              @johnpoz "The [upstream] firewall itself has host file entries for machines like Sia2 "

              Pre-2.7.2/23.09: Only install packages for your version, or risk breaking it. Select your branch in System/Update/Update Settings.
              When upgrading, allow 10-15 minutes to restart, or more depending on packages and device speed.
              Upvote ๐Ÿ‘ helpful posts!

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              • johnpozJ
                johnpoz LAYER 8 Global Moderator @SteveITS
                last edited by johnpoz

                @SteveITS said in Completely confused by DNS failure (dnsmasq):

                @johnpoz "The [upstream] firewall itself has host file entries for machines like Sia2 "

                It didn't send them, unless you edited the response.

                edit: oh I see you did some more posts... Pretty sure sure dnsmasq also does rebind protection.. When you forward a rfc1918 response is not going to be returned to the client.. Unless you have turned off rebind or have setup a domain to be private and allowed to return rfc1918

                https://docs.netgate.com/pfsense/en/latest/services/dns/rebinding.html

                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 2.7.2, 24.11

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                • S
                  SteveITS Galactic Empire @johnpoz
                  last edited by

                  @johnpoz said in Completely confused by DNS failure (dnsmasq):

                  When you forward a rfc1918 response is not going to be returned to the client

                  Ah yes there it is.

                  Pre-2.7.2/23.09: Only install packages for your version, or risk breaking it. Select your branch in System/Update/Update Settings.
                  When upgrading, allow 10-15 minutes to restart, or more depending on packages and device speed.
                  Upvote ๐Ÿ‘ helpful posts!

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                  • N
                    NickJH
                    last edited by

                    Yes, it could be rebind protection as I expect it to return a private IP (172.17.2.51). It is late here so I'll have a look in the morning.

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                    • N
                      NickJH
                      last edited by NickJH

                      I can confirm it was rebind protection causing it. I have disabled it and am using the the DNS Resolver successfully in forwarder mode. Thanks.

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                      • johnpozJ
                        johnpoz LAYER 8 Global Moderator @NickJH
                        last edited by

                        @NickJH dig you disable it globally? I would suggest just setting your domain your forwarding for and want rfc1918 vs turning it completely off.

                        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 2.7.2, 24.11

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                        • N
                          NickJH @johnpoz
                          last edited by

                          @johnpoz Yes I did it globally. I don't know how to do it by domain only, but it does not matter as pfSense is on my LAN for testing/learning. When I deploy it properly, I'll be turning it back on. It is just that it was interfering with my testing.

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                          • S
                            SteveITS Galactic Empire @NickJH
                            last edited by

                            @NickJH for reference itโ€™s on that doc page:

                            โ€œTo exclude a domain from DNS rebinding protection, use the Custom Options box in the DNS resolver settings. Enter one domain per line in the following format, preceded by the server: line.

                            server:
                            private-domain: "example.com"
                            private-domain: "dnsbl.example"
                            โ€œ

                            I just forget about this โ€œfeatureโ€ because itโ€™s rarely needed, but we had to discover/use it ourselves 10 years ago.

                            Pre-2.7.2/23.09: Only install packages for your version, or risk breaking it. Select your branch in System/Update/Update Settings.
                            When upgrading, allow 10-15 minutes to restart, or more depending on packages and device speed.
                            Upvote ๐Ÿ‘ helpful posts!

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                            • johnpozJ
                              johnpoz LAYER 8 Global Moderator @NickJH
                              last edited by johnpoz

                              @NickJH how to do that was right in the link I posted..

                              For both unbound and dnsmasq

                              I take it you didn't read past the "This behavior is controlled by the DNS Rebind Check option under System > Advanced, Admin Access tab." part ;)

                              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 2.7.2, 24.11

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                              • N
                                NickJH @johnpoz
                                last edited by

                                @johnpoz All I needed was a quick and dirty fix because it is not going to be the production set up. I did the fix late yesterday but it was about 10pm and if the quick and dirty was going to fix it, it was good enough for me. I only tested it this morning.

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                                • C
                                  cb831 @johnpoz
                                  last edited by

                                  @johnpoz Thanks for this I have been through the same debugging process as @NickJH. The documentation for DNS forwarder says "To exclude a domain from DNS rebinding protection, use the DNS forwarder Advanced Settings box as follows:" - It should be "...Custom Settings".

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                                  • S
                                    SteveITS Galactic Empire @cb831
                                    last edited by

                                    @cb831 There's a "Give Feedback" link at the top of each doc page. It probably got renamed at some point.

                                    Pre-2.7.2/23.09: Only install packages for your version, or risk breaking it. Select your branch in System/Update/Update Settings.
                                    When upgrading, allow 10-15 minutes to restart, or more depending on packages and device speed.
                                    Upvote ๐Ÿ‘ helpful posts!

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                                    • johnpozJ
                                      johnpoz LAYER 8 Global Moderator @SteveITS
                                      last edited by johnpoz

                                      @SteveITS yeah I would highly doubt there has been much work on the forwarder (dnsmasq) in quite some time to be honest. I am surprised that anyone would still be using it to be honest.. I mean it can do some things unbound can't like forward to multiple NS as the same time, etc.

                                      But if you can't figure out that the custom options box is what they were talking about - not sure what to tell you ;)

                                      Now if there was 2 boxes, one labeled advanced, and the other custom - and putting it in advanced didn't work because they called out the wrong box - yeah that could be problematic.. But there is only one possible place such commands could be put into that gui form.

                                      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 2.7.2, 24.11

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