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    [SOLVED] Block smtp (25) on LAN network. Only allow mailserver to send mail

    Scheduled Pinned Locked Moved Firewalling
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    • johnpozJ
      johnpoz LAYER 8 Global Moderator @Herman
      last edited by

      @herman said in Block smtp (25) on LAN network. Only allow mailserver to send mail:

      All clients first DNS entry

      Are you saying they have more than 1 and this points to pfsense? Yeah that is Borked and going to cause you grief in the long run. You can not point to clients to more than 1 dns when the different dns does not resolve the same stuff. ie you do not point to local dns, and 2nd point to public dns - because public dns can not resolve local.

      You can never be sure which dns client will actually use..

      Point your clients ONLY to NS that can resolve your AD.. if pfsense can not resolve your AD then clients should not have it in their list for dns.

      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

      HermanH 1 Reply Last reply Reply Quote 0
      • HermanH
        Herman @johnpoz
        last edited by

        @johnpoz Right, double checked it. All clients have only one DNS server pointing to the DC hosting the DNS role.

        Greetz,
        Herman

        Limburg | The Netherlands.
        It is nice to be important. But it is more important to be nice! | Failure, the best teacher it is!

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        • johnpozJ
          johnpoz LAYER 8 Global Moderator
          last edited by

          Well than pfsense has ZERO to do with device on lan talking to another device on lan.. If your having problems with outlook talking to your exchange that are on the same network - what do you think pfsense has to do with that conversation?

          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

          HermanH 1 Reply Last reply Reply Quote 1
          • HermanH
            Herman @johnpoz
            last edited by

            @johnpoz

            Doesn’t make sense to me at all too. Since I’ve implemented the pfSense firewall this issues start to occur.

            Should the something be configured in the DNS resolver of the pfSense? Shouldn’t it also point to the DC’s DNS?

            Limburg | The Netherlands.
            It is nice to be important. But it is more important to be nice! | Failure, the best teacher it is!

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            • HermanH
              Herman @Herman
              last edited by

              @herman Found the problem! I am also migrating Exchange 2013 to Exchange 2016. Since the 2016 box was off because I paused the migration, Outlook was still trying to resolve the public folders on the 2016 box. Turn the machine on resolved the problem.

              Sorry for the inconvenience. My bad!

              But still wondering if I should setup anything for the DNS resolver of the pfSense?

              Cu,
              Herman

              Limburg | The Netherlands.
              It is nice to be important. But it is more important to be nice! | Failure, the best teacher it is!

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              • DerelictD
                Derelict LAYER 8 Netgate
                last edited by

                I wouldn't. If anything I would set up a backup domain controller.

                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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                • HermanH
                  Herman @Derelict
                  last edited by

                  @derelict So you suggest to leave the DNS Resolver on pfSense box disabled?

                  Gr. Herman

                  Limburg | The Netherlands.
                  It is nice to be important. But it is more important to be nice! | Failure, the best teacher it is!

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                  • DerelictD
                    Derelict LAYER 8 Netgate
                    last edited by

                    https://forum.netgate.com/post/778596

                    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)

                    HermanH 1 Reply Last reply Reply Quote 1
                    • HermanH
                      Herman @Derelict
                      last edited by

                      @derelict Thank you. Now it look like i would expect it to look. Even the ARP table is resolving the right hostname now. 👍

                      Sorry if I keep going on but in the log file I see the folowing two entries. Any idea what they mean? port 67 and 68 is DHCP if I am correct.

                      0_1533333996466_Port 67 68 blocked.JPG

                      and

                      0_1533334018954_IGMP Blocked.JPG

                      That would be the last post for today. Have to go sleeping 😁

                      Thanks to everybody for the kind support. CU soon.

                      Bye
                      Herman

                      Limburg | The Netherlands.
                      It is nice to be important. But it is more important to be nice! | Failure, the best teacher it is!

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

                        @herman If you are not running a DHCP server on pfSense you will not have the automatic pass rules for DHCP on your local network.

                        If you are limiting outbound connections and not passing any into the local interface, you might want to make a rule to block that traffic and not log it to kill that log spam. That is logging that a DHCP discover broadcast was received and not passed by the firewall.

                        Same with the IGMP if the log entries annoy you.

                        Or you could just turn off logging on the default deny rule entirely. Status > System Logs, Log firewall default blocks. For me it would depend on how many rules were necessary to get the log spam under control. If just a couple/few, I would make the rules. If it's a boatload, I'd probably just disable the logging entirely.

                        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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