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    Potential DNS Rebind attack detected on my local network

    Scheduled Pinned Locked Moved General pfSense Questions
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    • johnpozJ
      johnpoz LAYER 8 Global Moderator @comet424
      last edited by

      @comet424 not sure why anyone would use an actual public domain in pfsense. Unless you were using that internally - but that normally is idea that comes with many issues.

      now if you owned hell.com and used hell.net internally where hell.net did not resolve on the public internet that would be one thing. But trying to leverage public domain externally and internally at the same time runs into problems. And is not really a suggested setup.

      The 2 approved domains to use internally these days is home.arpa and .internal

      I would suggest you use one of those..

      Kea is not as yet at feature parity with isc (older dhcp server).. And it is missing features.. I would not suggest you use it currently unless you have the most basic requirements of a dhcp server. There are some good strides to bring it to parity with isc in the 24.11 release..

      Since tardis did not come back fq in your ping - that really points to just windows finding it with some other method where dns isn't even involved.

      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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        comet424 @johnpoz
        last edited by

        @johnpoz
        ok i changed localdomain to home.arpa

        as for dhcp settings all i set is
        192.168.0.50-254 as range
        dns 192.168.0.1
        gateway 192.168.0.1 and i do the same for my vlans
        so dns 192.168.10.1 and gateway for cameras and so on
        so if thats basic then ya i set my up basic

        and ubuntu and my other unraid boxes can now ping tardis and get the same results
        no domain name added... do they use other methods then too

        always learning something new everyday.. and the 24.11 release is that pfsense being released this month i know i had issues when i had 2.7.1 it didnt even know there was an update and when i transitioned to 2.7.2 there was a bunch of glitches in the config file and such that... so i manually re set up everything so entering in all manually so its glitch free.. so hope next upgrade no issues

        johnpozJ 1 Reply Last reply Reply Quote 0
        • johnpozJ
          johnpoz LAYER 8 Global Moderator @comet424
          last edited by johnpoz

          @comet424 have no idea what your doing on your linux boxes.. But if the name was discovered via DNS, then it should come back fq

          root@UC:/home/user# ping nas
          PING nas.home.arpa (192.168.9.10) 56(84) bytes of data.
          64 bytes from nas.home.arpa (192.168.9.10): icmp_seq=1 ttl=63 time=1.37 ms
          64 bytes from nas.home.arpa (192.168.9.10): icmp_seq=2 ttl=63 time=0.731 ms
          64 bytes from nas.home.arpa (192.168.9.10): icmp_seq=3 ttl=63 time=0.489 ms
          

          that is a linux box on my network. See I ping nas and it comes back nas.home.arpa - do you have host file on your linux box?

          My resolv.conf on my linux box has search set for home.arpa

          nameserver 127.0.0.53
          options edns0 trust-ad
          search home.arpa
          

          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
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            comet424 @johnpoz
            last edited by

            @johnpoz
            apparently i spoke too soon.. i had to reboot my unraid.. my other unraid can ping tardis thats rambo... but the ubuntu desktop it cant ping now
            pinging from unraid to tardis

            root@Rambo:~# ping tardis
            PING tardis (192.168.0.3) 56(84) bytes of data.
            64 bytes from Tardis.local (192.168.0.3): icmp_seq=1 ttl=64 time=0.267 ms
            64 bytes from Tardis.local (192.168.0.3): icmp_seq=2 ttl=64 time=0.227 ms
            64 bytes from Tardis.local (192.168.0.3): icmp_seq=3 ttl=64 time=0.313 ms
            64 bytes from Tardis.local (192.168.0.3): icmp_seq=4 ttl=64 time=0.391 ms
            64 bytes from Tardis.local (192.168.0.3): icmp_seq=5 ttl=64 time=0.285 ms
            ^C
            --- tardis ping statistics ---
            5 packets transmitted, 5 received, 0% packet loss, time 4089ms
            rtt min/avg/max/mdev = 0.227/0.296/0.391/0.054 ms
            

            pinging from ubuntu to tardis
            cant ping.png

            so i spoke too soon that everything working

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            • stephenw10S
              stephenw10 Netgate Administrator
              last edited by

              It looks like you made it work by removing the search domain from the client so it really is trying to resolve just 'tardis'. But some (many?) devices won't allow that.

              You should send the local domain via DHCP and then set the host overides using that domain.

              In Ubuntu you may need to flash the local resolver cache: sudo resolvectl flush-caches

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                comet424 @stephenw10
                last edited by

                @stephenw10 ah ok so i set the dhcp server domain i put in home.arpa
                and i rebooted the ubuntu desktop but still up able to ping tardis
                i can ping www.google.ca that has no problem it cant ping locally

                so you mean many devices wont allow you to ping tardis or like ping camera10
                as example or all my ESP32 devices that run esphome

                as for the host override... how do i blank host override to add domain and covers everything on the network.. as so far i only learned you can do like 1 ip address at a time

                and i read about split dns and 1:1 nat but all i remember is when i defaulted a clean pfsense i could ping ubuntu and stuff but now where i added vpn and the 1::128 and all those other nats i also wondered if those conflict?

                but so far i can ping from
                raspberry pi
                unraid
                windows
                pfsense

                but i cant seem to ping from any of my ubuntu vms

                and i thought if i set dns 192.168.0.1 and in the resolver i set it to all all for incomming and out going that it would resolve things but i guesss not

                and even after the reboot and the sudo resolvectl flush-caches i still get same error temporary failture..
                i did try this it also failed
                arpa.png

                if you can show with picture how my host override should look like that would cover everything be good as im a visual learner more over then words to understand things

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                • C
                  comet424 @comet424
                  last edited by

                  so i tried these 2 different over rides but these didnt work
                  domain.png host.png

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                  • C
                    comet424 @comet424
                    last edited by comet424

                    so with those 2 overrides i have i still can ping from
                    unraid
                    windows

                    but
                    ubutunu
                    raspberry pi

                    gives me issues cant resolve it... is that what you ment many cant resolve tardis just hostname

                    but what i dont understand is
                    i tell dhcp that the dns 192.168.0.1 so all clients know pfsense is to dns resolve all the local hostnames... i dont understand why it doesnt do it least not from ubuntu and raspberry pi.. and now i said that the domain that 192.168.0.1 the dns resolver needs to resolve all but it doesnt seem to be working

                    and here the arpa list the ubuntu desktop doesnt have no .home.arpa.. or the example i gave hell.com so pfsense should be resolving the hostnames no matter what os im pinging from right? least thats how i thought it works
                    dhcpa.png
                    dhcpab.png

                    i tried custom options

                    server:
                    private-domain: "home.arpa"
                    

                    that didnt help either

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                    • stephenw10S
                      stephenw10 Netgate Administrator
                      last edited by

                      In the host override you have to add both the host and the domain. In your example you have added a hostoverride with no host!

                      Domain overrides point to a specific DNS server for the whole domain. You don't want that here.

                      Try using dig in ubuntu so you know it's actually querying Unbound in pfSense.

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                        comet424 @stephenw10
                        last edited by

                        @stephenw10
                        ok so remove the host and domain override.. i did the domain and pointed it to 192.168.0.1 so it would do all local hostnames least thats how i thought

                        what about that private-domain i added too how does that work?

                        as for ubuntu and dig command these are the screen shots
                        i thought once u tell dhcp dns is 192.168.0.1 all OSs would be resolved by pfsense
                        ub1.png ub2.png ub3.png

                        johnpozJ 1 Reply Last reply Reply Quote 0
                        • johnpozJ
                          johnpoz LAYER 8 Global Moderator @comet424
                          last edited by

                          @comet424 that is not what he meant by a dig..

                          dig tardis.home.arpa

                          Your linux is using a local cache, that is why it points to127.0.0.53, if you want to know where that points.

                          user@UC:~$ resolvectl status
                          Global
                                 Protocols: -LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
                          resolv.conf mode: stub
                          
                          Link 2 (ens3)
                              Current Scopes: DNS
                                   Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
                          Current DNS Server: 192.168.3.10
                                 DNS Servers: 192.168.3.10
                                  DNS Domain: home.arpa
                          user@UC:~$ 
                          

                          Private-domain sets a domain so that if you forward for that domain it will turn off rebind protection

                          You are making this so freaking difficult.. Out of the box dhcp will hand out the domain is set in general setup, ie home.arpa for example.. Your client may or may not use that..

                          When you query for dns, it has to be fully qualified, so either query the fqdn - ie tardis.home.arpa or make sure your client is using search suffix and will auto add it for you.

                          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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                            comet424 @johnpoz
                            last edited by

                            @johnpoz
                            sorry not trying to make it complicated.. all i thought is once you set it up in pfsense under dhcp server
                            your gate way and dns.. then pfsense did all the resolving of the local hostnames for any operating system.. i not familar with ubuntu alot so i just noticed i cant ping ill have to look up what a fqdn is

                            and all i want is once dhcp server shells out the ip then it doesnt matter what os... just be able to ping and access by the hostname in the arpa table so whatever i have to do to make it auto work like it auto works in unraid and windows.. but then you mention windows does its own thing

                            as for the dig and resolvectl this is the result
                            ub4.png

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                            • stephenw10S
                              stephenw10 Netgate Administrator
                              last edited by

                              Try: dig @192.168.0.1 tardis.home.arpa.

                              In that example:

                              tardis is a hostname

                              home.arpa is a domain

                              tardis.home.arpa is a fully qualified domain name (fqdn).

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                              • johnpozJ
                                johnpoz LAYER 8 Global Moderator @comet424
                                last edited by johnpoz

                                @comet424 did you leave that domain forward in there - that is pointless, and prob going to break it.

                                Unless your register dhcp or static reservations. Unbound doesn't have a clue about other hosts you have on your network.

                                So you would either need to do one of those or both, and or just create a host override..

                                tardis.jpg

                                is 192.168.0.1 pfsense IP? Or some other NS?

                                Unbound wouldn't normally return a SOA like that.

                                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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                                • C
                                  comet424 @johnpoz
                                  last edited by comet424

                                  @johnpoz
                                  so i removed that domain and host override yesterday... only thing for domain i left i guess i should remove is

                                  server:
                                  private-domain: "home.arpa"
                                  

                                  i can delete that

                                  192.168.0.1 is pfsense 192.168.0.3 is the tardis
                                  so host overide.. so i have to manaully enter then 200+ ips for ubuntu to be able to access them then ? like i always though under the ARP table the host name you could always ping or access the device by the hostname thats how i do it in unraid or windows like my 30+ ESP devices or all my IOT devices just access them by the Hostname through windows browser or ssh etc..

                                  what is a SOA?

                                  @stephenw10
                                  this is the result of the dig @192.168.0.1 tardis.home.arpa.

                                  ub5.png
                                  arp1.png

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                                  • johnpozJ
                                    johnpoz LAYER 8 Global Moderator @comet424
                                    last edited by johnpoz

                                    @comet424 SOA is a record saying hey have no record of that - you should prob go ask the SOA (source of authority).. Out of the box unbound wouldn't return that record.. you would of had to create it.

                                    If in the default transparent mode and you ask for anything.home.arpa and there is no record it would try and resolve it upstream, and that wouldn't return that soa either.

                                    for home.arpa that you tried to resolve and had no record of and got sent upstream the soa would be

                                    ;; QUESTION SECTION:
                                    ;fsljfdsdf.home.arpa.           IN      A
                                    
                                    ;; AUTHORITY SECTION:
                                    home.arpa.              3600    IN      SOA     prisoner.iana.org. hostmaster.root-servers.org. 1 604800 60 604800 604800
                                    

                                    what do you have in the custom box of unbound? Do you have some host overrides setup.. domain overrides? unbound would not return that nobody soa

                                    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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                                    • stephenw10S
                                      stephenw10 Netgate Administrator @comet424
                                      last edited by

                                      @comet424 said in Potential DNS Rebind attack detected on my local network:

                                      @stephenw10
                                      this is the result of the dig @192.168.0.1 tardis.home.arpa.

                                      Sorry that last . was outside the quote! Muscle memory forced me to type it. 😉

                                      The command should be:

                                      dig @192.168.0.1 tardis.home.arpa

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                                      • johnpozJ
                                        johnpoz LAYER 8 Global Moderator @stephenw10
                                        last edited by

                                        @stephenw10 that wouldn't matter, and dig does it by default anyway unlike nslookup

                                        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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                                        • stephenw10S
                                          stephenw10 Netgate Administrator
                                          last edited by stephenw10

                                          Given the presence of Nord and PIA do you have Unbound in forwarding mode to other upstream servers over the VPN?

                                          None of that should matter though, Unbound should still respond with hostoverrides in place.

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                                            comet424 @stephenw10
                                            last edited by comet424

                                            @stephenw10
                                            @johnpoz
                                            so for custom options in dns resolver i have

                                            server:
                                            local-zone: "windowsupdate.com" redirect
                                            local-data: "windowsupdate.com 86400 IN A 192.168.0.32"
                                            
                                            server:
                                            local-zone: "microsoft.com.edgesuite.net" redirect
                                            local-data: "microsoft.com.edgesuite.net 86400 IN A 192.168.0.32"
                                            
                                            server:
                                            local-zone: "update.microsoft.com" redirect
                                            local-data: "update.microsoft.com 86400 IN A 192.168.0.32"
                                            
                                            server:
                                            local-zone: "do.dsp.mp.microsoft.com" redirect
                                            local-data: "do.dsp.mp.microsoft.com 86400 IN A 192.168.0.32"
                                            
                                            server:
                                            local-zone: "dl.delivery.mp.microsoft.com" redirect
                                            local-data: "dl.delivery.mp.microsoft.com 86400 IN A 192.168.0.32"
                                            
                                            server:
                                            local-zone: "cdn.blizzard.com" redirect
                                            local-data: "cdn.blizzard.com 86400 IN A 192.168.0.32"
                                            
                                            server:
                                            private-domain: "home.arpa"
                                            
                                            server:include: /var/unbound/pfb_dnsbl.*conf
                                            

                                            my host over ride is
                                            host1.png host2.png

                                            the
                                            dig @192.168.0.1 tardis.home.arpa command without the extra .

                                            dig.png

                                            dns resolver i set to all all so i can then do the bypass routing policy on Lan
                                            dns1.png

                                            i disabled NordVPN and switched over to PIA they do different things... like no proper video for PIA but one had NAT just 192.168.0.0 and another used the pia for 1::128 and those other generated in NAT table so i dubbed them like i read in a PIA setup tutorial.. its like there is different ways to set up there vpn..

                                            i dont use the DNS forwarder... as it wasnt part of the setup of PIA or norvpn in the past.. and i think i read or watched you cvan have dns resolver and forwarder same time?

                                            only other VPN i use is Site to Site to my sisters Pfsense so i can access her network like it was here.. and i have to re add remote access...

                                            and this is my LAN rules
                                            rules1.png rules2.png

                                            rules3.png
                                            any other screen shots you need..

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