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    Potential DNS Rebind attack detected on my local network

    Scheduled Pinned Locked Moved General pfSense Questions
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    • C
      comet424 @comet424
      last edited by

      there was a couple ways people setup PIA VPN so reason i have wan and pia toronto ::1/128 and all those whatever they all mean
      and another video didnt

      so i not sure if that has anything to do with it etc

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

        @comet424 not sure where your getting your dns from, but hell.com does not return a 69.x here

        hell.com.               3600    IN      A       15.
        hell.com.               3600    IN      A       3.
        

        And tardis.hell.com doesn't even resolve on the public internet.. So not sure where your getting 69.x from? and a 69.x would not be a rebind anyway. A rebind is when unbound forwards to anywhere or resolves itself, ie its not a local resource that gets sent in the answer and that answer contains rfc1918 address space. If 69.x is returned that would not be a rebind.

        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

          You can see the windows client has hell.com set as the search suffix. That means when you try to resolve 'tardis' it actually queries for tardis.hell.com to make a valid fqdn.

          If you add host overrides to Unbound via the GUI you have to set the domain so they would be valid but in your custom Unbound conf settings you have omitted the domain so it doesn't match.

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          • C
            comet424 @stephenw10
            last edited by

            @johnpoz i mentioned that i changed my actual dynns name to hell.com and i changed my actaual WAN IP to 69.x.x.x replacing the actual numbers with x

            as was easier to do Find and Replace then screen shot and black out the actual dns name
            as i learned your supposed to block it out thats why i mentioned i actually changed it... guess i should said i changed it for display purpose only my bad for miss representing

            @stephenw10
            1
            so why does windows get the hell.com (display purpose only) in the serach suffix

            would the original pfsense setup be search suffix "workgroup" or
            how would i remove the search suffix wouldnt that solve the problem bring it back to default thats how it always worked?

            2
            so if i do the unbound thats the dns resolver.. the custom and would you type it then

            server:
            local-zone: "pump.hell.com" redirect
            local-data: "pump.hell.com 86400 IN A 192.168.0.10"

            and when do you use
            server:
            private-domain: "tardis"
            private-domain: "pump"

            so do you have to type it
            server:
            private-domain: "tardis.hell.com"
            private-domain: "pump.hell.com"

            but this woulld get to be a long list.. if everytime you add a new device to the home network you gotta add it to the custom override. and if the ip address changes then it wont work...

            the best route be removing the search suffix but how did it get in there in the first place... is there a check box in pfsense that set it... like the
            DNS Server Override Allow DNS server list to be overridden by DHCP/PPP on WAN or remote OpenVPN server

            would that solve it.. as i dont need my local computers with with .hell.com on the end of it just a home setup not a big company with servers

            and if i can remove the search suffix will it bring it back to default how it worked originally that im used to?

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            • C
              comet424 @comet424
              last edited by

              under dhcp server i looked at lan
              i blacked out the blank doman location

              if i just put a spacebar to remove the default will that fix that
              i just dont know how i caused it to have this problem a simple check box?
              when i transitioned from NordVPN to PIA VPN?

              dhcp11.png

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              • C
                comet424 @comet424
                last edited by comet424

                ok i think i fixed it

                i googled domain name of pfsense
                i changed it back to "localdomain"
                i guess when i did a new pfsense setup and it asked about domain name i used what i had in my dyndns updater...

                its back to working i can ping
                tardis
                and go to
                http://tardis

                and it goes to 192.168.0.3
                wish i was more smarter at this stuff

                @johnpoz @stephenw10
                i apperciate your both helps.. without your help i wouldnt have tried changing domain name to localdomain as it was frustrating with your help i figured it out i really appreciate it

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

                  @comet424 that really should have zero to do with it..

                  but now when you ping tardis, does it comeback tardis.localdomain? does it comeback without a domain? If so then dns was was not used. And your client used some other method to find tardis, be it mdns, or just a broadcast, etc.

                  Do you have registration of dhcp clients set in unbound? Are you using isc or kea dhcp server?

                  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
                    when i ping it no i dont get localdomain i get

                    C:\Users\mike>ping tardis
                    
                    Pinging tardis [192.168.0.3] with 32 bytes of data:
                    Reply from 192.168.0.3: bytes=32 time<1ms TTL=64
                    Reply from 192.168.0.3: bytes=32 time<1ms TTL=64
                    Reply from 192.168.0.3: bytes=32 time<1ms TTL=64
                    Reply from 192.168.0.3: bytes=32 time<1ms TTL=64
                    
                    Ping statistics for 192.168.0.3:
                        Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
                    Approximate round trip times in milli-seconds:
                        Minimum = 0ms, Maximum = 0ms, Average = 0ms
                    
                    C:\Users\mike>ipconfig /all
                    
                    Windows IP Configuration
                    
                       Host Name . . . . . . . . . . . . : Windows11-Gaming-Desktop
                       Primary Dns Suffix  . . . . . . . :
                       Node Type . . . . . . . . . . . . : Hybrid
                       IP Routing Enabled. . . . . . . . : No
                       WINS Proxy Enabled. . . . . . . . : No
                       DNS Suffix Search List. . . . . . : localdomain
                    
                    Ethernet adapter 10Gig Nic:
                    
                       Connection-specific DNS Suffix  . : localdomain
                       Description . . . . . . . . . . . : Intel(R) 82599 10 Gigabit Network Connection
                       Physical Address. . . . . . . . . : 98-B7-85-1F-A0-B1
                       DHCP Enabled. . . . . . . . . . . : Yes
                       Autoconfiguration Enabled . . . . : Yes
                       Link-local IPv6 Address . . . . . : fe80::a570:4985:f868:8d21%12(Preferred)
                       IPv4 Address. . . . . . . . . . . : 192.168.0.151(Preferred)
                       Subnet Mask . . . . . . . . . . . : 255.255.255.0
                       Lease Obtained. . . . . . . . . . : Friday, November 22, 2024 11:16:38 AM
                       Lease Expires . . . . . . . . . . : Friday, November 22, 2024 1:16:37 PM
                       Default Gateway . . . . . . . . . : 192.168.0.1
                       DHCP Server . . . . . . . . . . . : 192.168.0.1
                       DHCPv6 IAID . . . . . . . . . . . : 714651525
                       DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-2D-34-A3-5E-C8-7F-54-55-89-B8
                       DNS Servers . . . . . . . . . . . : 192.168.0.1
                       NetBIOS over Tcpip. . . . . . . . : Enabled
                    
                    C:\Users\mike>
                    

                    the way it originally worked

                    im using kea dhcp as i learned pfsense said the other is depreciating
                    i dont know what isc unless thats the old dhcp and no dhcp clients in the custom override if thats what u mean by unbound

                    although i set in dhcp server lan i static set tardis to be 192.168.0.3

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                    • C
                      comet424 @comet424
                      last edited by

                      and if that solves my issue i was having and i use dyndns for my domain name
                      by changing domain to localdomain under general

                      just curiousity when do you use domain under general to be like the hell.com as display pupose example
                      is that for when you have a big company... or something as i always trying to learn stuff new everyday so curious when and when you dont use that

                      johnpozJ 1 Reply Last reply Reply Quote 0
                      • 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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                        • C
                          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
                            SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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                            • C
                              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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                                • C
                                  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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                                        • C
                                          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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