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

      http://tardis/
      and just redirects me to 192.168.0.3

      that is not any sort of valid config.. that is not fqdn, how would dns resolve that? Now your client could add a search suffix to that, but that is on the client to do.

      example

      $ ping nas
      
      Pinging nas.home.arpa [192.168.9.10] with 32 bytes of data:
      Reply from 192.168.9.10: bytes=32 time=1ms TTL=64
      

      See how it comes back nas.home.arpa, that is because when the dns query was done, my client auto added the domain.

      $ ipconfig /all
      
      Windows IP Configuration
      
         Host Name . . . . . . . . . . . . : i9-win
         Primary Dns Suffix  . . . . . . . : home.arpa
         Node Type . . . . . . . . . . . . : Broadcast
         IP Routing Enabled. . . . . . . . : No
         WINS Proxy Enabled. . . . . . . . : No
         DNS Suffix Search List. . . . . . : home.arpa
      

      If you notice with a simple nslookup

      nslookup.jpg

      If your getting back some wan IP in your query that goes to the internet, then your client is most likely adding some public domain in the query.

      If your client asks unbound on pfsense for www.tardis.hell.com and you want that to redirect some local IP, you would need a override.. But just going to tardis, what is it actually asking for via the FQDN?

      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

      C 1 Reply Last reply Reply Quote 1
      • C
        comet424 @johnpoz
        last edited by comet424

        @johnpoz
        so like when i orginally setup pfsense it worked out of the box

        http://tardis pfsense redirects to 192.168.0.3 unraid server
        http://pump:8123 pfsense would redirect to 192.168.0.10 home asstant server
        if i pinged tardis
        id get tardis 192.168.0.3
        no tardis.hell.com

        same with the cameras all i type in the address bar
        camera1/
        camera2/ and pfsense rediects it to 192.168.10.50 say
        least thats how it used to work

        so i ran your nslookup set debug
        i changed the actual ip but left it startting as 69. and i changed my dyns to hell.com

        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. . . . . . : hell.com
        
        Ethernet adapter 10Gig Nic:
        
           Connection-specific DNS Suffix  . : hell.com
           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 15, 2024 5:54:28 PM
           Lease Expires . . . . . . . . . . : Friday, November 22, 2024 12:17:08 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>nslookup
        Default Server:  pfSense.hell.com
        Address:  192.168.0.1
        
        > tardis
        Server:  pfSense.hell.com
        Address:  192.168.0.1
        
        Non-authoritative answer:
        Name:    hell.com
        Address:  69.x.x.x
        Aliases:  tardis.hell.com
        
        > set debug
        > tardis
        Server:  pfSense.hell.com
        Address:  192.168.0.1
        
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 4, rcode = NOERROR
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 2,  authority records = 0,  additional = 0
        
            QUESTIONS:
                tardis.hell.com, type = A, class = IN
            ANSWERS:
            ->  tardis.hell.com
                canonical name = hell.com
                ttl = 49 (49 secs)
            ->  hell.com
                internet address = 69.x.x.x
                ttl = 49 (49 secs)
        
        ------------
        Non-authoritative answer:
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 5, rcode = NOERROR
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 1,  authority records = 1,  additional = 0
        
            QUESTIONS:
                tardis.hell.com, type = AAAA, class = IN
            ANSWERS:
            ->  tardis.hell.com
                canonical name = hell.com
                ttl = 49 (49 secs)
            AUTHORITY RECORDS:
            ->  mine.nu
                ttl = 1789 (29 mins 49 secs)
                primary name server = ns1.dyndns.org
                responsible mail addr = hostmaster.dyndns.org
                serial  = 2525007979
                refresh = 900 (15 mins)
                retry   = 300 (5 mins)
                expire  = 604800 (7 days)
                default TTL = 1800 (30 mins)
        
        ------------
        Name:    hell.com
        Address:  69.x.x.x
        Aliases:  tardis.hell.com
        

        as for FQDN? i have no idea just simple home user

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        • C
          comet424 @comet424
          last edited by

          here is my lan rules and my dns resolver
          2.png p1.png p3.png

          C 1 Reply Last reply Reply Quote 0
          • C
            comet424 @comet424
            last edited by

            and here is my nat rules

            if that helps at all
            nn1.png nn2.png nn3.png

            C johnpozJ 2 Replies Last reply Reply Quote 0
            • 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 2.8, 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 2.8, 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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                              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 2.8, 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
                                    SG-4860 24.11 | Lab VMs 2.8, 24.11

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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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                                            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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