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    DNS leaks using OpenVPN client tunnel

    Scheduled Pinned Locked Moved OpenVPN
    69 Posts 7 Posters 25.4k Views
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    • DerelictD
      Derelict LAYER 8 Netgate
      last edited by

      That second rule will never match because the traffic will be matched by the any rule above it and policy routed out the VPN.

      Note the 0/0 counters there.

      Chattanooga, Tennessee, USA
      A comprehensive network diagram is worth 10,000 words and 15 conference calls.
      DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
      Do Not Chat For Help! NO_WAN_EGRESS(TM)

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      • G
        gschmidt
        last edited by

        Right!…I changed the order...but still...leaking Google and OpenDNS (which i did not specify anywhere in pfsense)

        NAT-02.jpg = NAT Redirection of ExpressVPN DNS servers

        Result= dnsleaktest.jpg

        NAT-rule-01.JPG
        NAT-rule-01.JPG_thumb
        NAT-rule-02.JPG
        NAT-rule-02.JPG_thumb
        dnsleaktest.JPG
        dnsleaktest.JPG_thumb

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        • DerelictD
          Derelict LAYER 8 Netgate
          last edited by

          WHAT DNS SERVERS ARE YOUR CLIENTS SET TO USE?

          DNS is NOT this hard, people.

          With your rules like that, the express_vpn_dns servers will be queried using the default gateway, NOT the VPN, unless you have redirect gateway for the VPN itself.

          Chattanooga, Tennessee, USA
          A comprehensive network diagram is worth 10,000 words and 15 conference calls.
          DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
          Do Not Chat For Help! NO_WAN_EGRESS(TM)

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          • S
            strangegopher
            last edited by

            @gschmidt:

            I have specified the Google servers at System/General Setup/DNS Server Settings

            No need to do this as unbound by default uses root servers for dns, so no need for dns forwarding.
            If you want you can remove all the dns servers from this section and dns will still work.

            above or under which rule should your "I am also blocking any access to dns server on the firewall" rule be located?

            Sorry I posted the wrong image.
            This is what the dns rule should look like:
            (above all other rules in your case [except anti-lockout])
            Action: Block
            Protocol: IPv4 TCP/UDP
            Source: ExpressVPN_Hosts
            Src Port: Any
            Destination: This Firewall
            Dst Port: 53 (DNS)

            That will block access to firewall's dns server.

            Now you will have to to do to is go to:
            Services/DHCP Server/LAN
            and Under DNS Servers add dns server of your choice (like google dns).

            Also like Derelict mentioned you can remove the 2nd rule of NAT redirection to expressvpn.
            And any other port forwarding rules u created under Firewall -> Nat.

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            • G
              gschmidt
              last edited by

              On the static DHCP mappings in pfSense (which is my main router): Empty
              On client 1 (Window 10 PC): automatically (which is the gateway 192.168.1.1)
              On client 2 (linux device): 192.168.1.1

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              • S
                strangegopher
                last edited by

                Do you not see this under Services/DHCP Server/LAN?

                Capture.PNG
                Capture.PNG_thumb

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                • DerelictD
                  Derelict LAYER 8 Netgate
                  last edited by

                  That DOES NOT MEAN that you do not have static DNS servers on the client you are testing, bro.

                  This really is. not. that. hard.

                  Chattanooga, Tennessee, USA
                  A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                  DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                  Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                  • G
                    gschmidt
                    last edited by

                    Ok….I have created the rule =Block rule.jpg
                    Added the google dns servers = "DHCP Server DNS Server.jpg"
                    and the ExpressVPN DNS servers = Static DHCP Mapping.jpg"

                    dnsleaktest result= dnsleaktest.jpg

                    :o

                    ![Block Rule.JPG](/public/imported_attachments/1/Block Rule.JPG)
                    ![Block Rule.JPG_thumb](/public/imported_attachments/1/Block Rule.JPG_thumb)
                    ![DHCP Server DNS Server.JPG](/public/imported_attachments/1/DHCP Server DNS Server.JPG)
                    ![DHCP Server DNS Server.JPG_thumb](/public/imported_attachments/1/DHCP Server DNS Server.JPG_thumb)
                    ![Static DHCP Mapping.JPG](/public/imported_attachments/1/Static DHCP Mapping.JPG)
                    ![Static DHCP Mapping.JPG_thumb](/public/imported_attachments/1/Static DHCP Mapping.JPG_thumb)
                    dnsleaktest.JPG
                    dnsleaktest.JPG_thumb

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                    • G
                      gschmidt
                      last edited by

                      I did an nslookup at the client W10 PC
                      Which shows the DNS server of ExpressVPN
                      Which I entered in the Static Mapping DNS servers in pfSense

                      nslookup.JPG
                      nslookup.JPG_thumb

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                      • S
                        strangegopher
                        last edited by

                        try removing the ExpressVPN DNS servers from Static DHCP Mapping and replacing it with 8.8.8.8 and 8.8.4.4

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                        • DerelictD
                          Derelict LAYER 8 Netgate
                          last edited by

                          It doesn't matter where anything is configured. What are the DNS servers configured on the client. Use ipconfig /all

                          Hell, if you're having this much trouble, configure them statically.

                          Chattanooga, Tennessee, USA
                          A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                          DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                          Do Not Chat For Help! NO_WAN_EGRESS(TM)

                          1 Reply Last reply Reply Quote 0
                          • G
                            gschmidt
                            last edited by

                            ipconfig /all

                            I dont see static dns servers?
                            Only the express vpn dns servers i have specified in pfsense

                            ipconfig-all.JPG
                            ipconfig-all.JPG_thumb

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                            • S
                              strangegopher
                              last edited by

                              my guess is expressvpn dns servers might be the issue, so try using 8.8.8.8 in windows go to Control Panel\Network and Internet\Network Connections right click your interface, select properties, double click "Internet Protocol Version 4", select "Use Following DNS server addresses" and enter 8.8.8.8 and 8.8.4.4

                              and run dns leak test again

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                              • G
                                gschmidt
                                last edited by

                                @strangegopher:

                                try removing the ExpressVPN DNS servers from Static DHCP Mapping and replacing it with 8.8.8.8 and 8.8.4.4

                                Check!…Still leaking Google and openDNS servers....looks exact the same as with the NAT redirection of port 53
                                I just did a default pfsense 2.4.2 setup (update to 2.4.3), nothing special

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                                • S
                                  strangegopher
                                  last edited by

                                  Well I am out of ideas then. I don't know what could be going wrong.

                                  1 Reply Last reply Reply Quote 0
                                  • DerelictD
                                    Derelict LAYER 8 Netgate
                                    last edited by

                                    What matters is that they are not coming from YOU. You cannot control where the resolvers you query go to get their information. If the resolvers you query don't do what you like, use different resolvers.

                                    Chattanooga, Tennessee, USA
                                    A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                                    DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                                    Do Not Chat For Help! NO_WAN_EGRESS(TM)

                                    1 Reply Last reply Reply Quote 0
                                    • G
                                      gschmidt
                                      last edited by

                                      @strangegopher:

                                      Well I am out of ideas then. I don't know what could be going wrong.

                                      Look now I have removed the DNS servers at System/General Setup
                                      And in DNS Resolver i set (see picture)
                                      In DHCP Server all DNS Servers are empty
                                      Also Clients have no DNS specified
                                      Your rule (stopped temporarily)

                                      See dnsleaktest pic!

                                      ![DNS Resolver.JPG](/public/imported_attachments/1/DNS Resolver.JPG)
                                      ![DNS Resolver.JPG_thumb](/public/imported_attachments/1/DNS Resolver.JPG_thumb)
                                      NoDNSleak.JPG
                                      NoDNSleak.JPG_thumb

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                                      • G
                                        gschmidt
                                        last edited by

                                        But with this setup, all my network clients use the EXPRESSVPN interface….so if this interface is down...no internet for all

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                                        • S
                                          strangegopher
                                          last edited by

                                          you can try setting the outgoing interface in dns to WAN and try with dhcp settings and firewall rule again and see if that works.

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                                          • G
                                            gschmidt
                                            last edited by

                                            @Derelict:

                                            What matters is that they are not coming from YOU. You cannot control where the resolvers you query go to get their information. If the resolvers you query don't do what you like, use different resolvers.

                                            ….my knowledge is not that fancy of pfsense I admit...but i knew that my clients did NOT have static dns servers
                                            On a simple modem with OPENWRT this was a piece of cake....on their forum they helped instead of shouting

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