Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    NAT forwarding into WireGuard Interface as LAN Interface

    Scheduled Pinned Locked Moved Firewalling
    35 Posts 3 Posters 4.3k Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • Bob.DigB
      Bob.Dig LAYER 8
      last edited by Bob.Dig

      Just to recap, you have a VPS in the internet, just with pfSense on it.
      At home you have a pfSense too and an email-server behind that.
      You have made a WireGuard tunnel between the two sites.

      Now what you can do is a port 25 forward from the VPS to your email-server at home. Also you can route outgoing traffic to port 25 using the VPS over that WG tunnel.

      Have a look at this video how to do a Site-to-Site VPN Using WireGuard and pfSense even if you don't have any other hosts on the VPS.

      1 Reply Last reply Reply Quote 0
      • B
        Bronko @viragomann
        last edited by Bronko

        @viragomann said in NAT forwarding into WireGuard Interface as LAN Interface:

        I didn't mention that option.

        I know, but it was my first run to disable NAT for a specific connection only, to avoid to disable NAT entirely given by the fact not only public routable interfaces on pfsense at Site-A.

        @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

        Just to recap, you have a VPS in the internet, just with pfSense on it.
        At home you have a pfSense too and an email-server behind that.
        You have made a WireGuard tunnel between the two sites.

        Perfect recap!

        @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

        Now what you can do is a port 25 forward from the VPS to your email-server at home. Also you can route outgoing traffic to port 25 using the VPS over that WG tunnel.

        Exactly my current configuration with NAT enabled at VPS (Site-A here).

        @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

        Have a look at this video how to do a Site-to-Site VPN Using WireGuard and pfSense even if you don't have any other hosts on the VPS.

        Already done.

        (and mentioned here:)
        @Bronko said in NAT forwarding into WireGuard Interface as LAN Interface:

        But machineMX doesn't knows anymore tun_wg0: 10.200.0.2 for routing (DNS only), solved by Policy Routing on Site-B as described here for ex.

        Resuming:
        How to disable NAT for these specific SMTP traffic flow to log real source IP of connecting mail server - currently replaced by 10.200.0.2 (tun_wg0 at Site-B) - at my machineMX?

        Bob.DigB V 2 Replies Last reply Reply Quote 0
        • Bob.DigB
          Bob.Dig LAYER 8 @Bronko
          last edited by Bob.Dig

          @Bronko said in NAT forwarding into WireGuard Interface as LAN Interface:

          How to disable NAT for these specific SMTP traffic flow to log real source IP of connecting mail server - currently replaced by 10.200.0.2 (tun_wg0 at Site-B) - at my machineMX?

          Please show your Port Forward on your VPS and also the config of your WG Interface for both. Outbound NAT for both should be automatic, nothing else. It is that easy...

          B 1 Reply Last reply Reply Quote 0
          • V
            viragomann @Bronko
            last edited by

            @Bronko said in NAT forwarding into WireGuard Interface as LAN Interface:

            Resuming:
            How to disable NAT for these specific SMTP traffic flow to log real source IP of connecting mail server - currently replaced by 10.200.0.2 (tun_wg0 at Site-B) - at my machineMX?

            If you direct this connection over HAproxy read again, what I wrote above.

            1 Reply Last reply Reply Quote 0
            • B
              Bronko @Bob.Dig
              last edited by

              @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

              Please show your Port Forward on your VPS and also the config of your WG Interface for both. Outbound NAT for both should be automatic, nothing else. It is that easy...

              Site-A (VPS):

              Screenshot from 2023-10-05 21-42-58.png

              Screenshot from 2023-10-05 21-47-45.png

              Screenshot from 2023-10-05 21-48-57.png

              Site-B (home):

              Screenshot from 2023-10-05 21-50-34.png

              Screenshot from 2023-10-05 21-51-54.png

              As mentioned, mail server at home - machineMX (at LAN_SEITE3) - is working for in- and outbound mails, but the replaced source ip of incomming mail server connections.

              @viragomann said in NAT forwarding into WireGuard Interface as LAN Interface:

              If you direct this connection over HAproxy read again, what I wrote above.

              Will double check it but to use HAProxy as a reverse proxy for the Postfix SMTP server, you need to enable Postscreen in Postfix. This doesn't worked for me at the first run...

              Bob.DigB B 2 Replies Last reply Reply Quote 0
              • Bob.DigB
                Bob.Dig LAYER 8 @Bronko
                last edited by Bob.Dig

                @Bronko I meant the complete IP-config from those interfaces, not their status.
                Also remove the manual outbound NAT rule and forget haproxy.
                And what rule is the last one? For the tunnel use an allow any rule for testing.

                B 1 Reply Last reply Reply Quote 0
                • B
                  Bronko @Bob.Dig
                  last edited by Bronko

                  @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

                  I meant the complete IP-config from those interfaces, not their status.

                  The tunnel is working fine, no problem here... isn't it?

                  @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

                  Also remove the manual outbound NAT rule and forget haproxy.

                  Without this rule @viragomann (above) incomming conntections via VPS at Site-A to machineMX at Site-B doesn't work.

                  @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

                  And what rule is the last one? For the tunnel use an allow any rule for testing.

                  An allow any rule for wg_tunnel is in place. These last one is policy routing for server net (LAN_SEITE3). Without these the outgoing traffic at server net is routed via default gateway at Site-A.

                  1 Reply Last reply Reply Quote 0
                  • B
                    Bronko @Bronko
                    last edited by Bronko

                    Let's have a picture here, port forwarding, outbound NAT and policy routing via rules from above:

                    Untitled.jpg

                    Described above:

                    Site-A

                    tun_wg0: 10.200.0.2

                    netstat -rn
                    Routing tables
                    
                    Internet:
                    Destination        Gateway            Flags     Netif Expire
                    default            xxxxxxxxxx         UGS      vtnet0
                    10.0.0.0/24        10.200.0.1         UGS     tun_wg0
                    10.200.0.0/24      link#6             U       tun_wg0
                    10.200.0.2         link#3             UHS         lo0
                    xxxxxxxxx/22       link#1             U        vtnet0
                    xxxxxxxxx          link#3             UHS         lo0
                    yyyyyyyyyyyyy      link#1             UHS      vtnet0
                    yyyyyyyyyyyyy      link#1             UHS      vtnet0
                    127.0.0.1          link#3             UH          lo0
                    192.168.0.0/16     10.200.0.1         UGS     tun_wg0
                    
                    

                    Screenshot from 2023-07-04 18-40-47.png

                    Site-B

                    tun_wg0: 10.200.0.1

                    netstat -rn
                    Routing tables
                    
                    Internet:
                    Destination        Gateway            Flags     Netif Expire
                    0.0.0.0/8          link#12            U         re0.8
                    default            xxxxxxxxxxxxx      UGS      pppoe0
                    10.0.0.0/24        link#18            U       re2.301
                    10.0.0.1           link#5             UHS         lo0
                    10.0.1.0/24        link#21            U        ovpns1
                    10.0.1.1           link#5             UHS         lo0
                    10.0.2.0/24        link#25            U        ovpns2
                    10.0.2.1           link#5             UHS         lo0
                    10.0.3.0/24        link#22            U        ovpns3
                    10.0.3.1           link#5             UHS         lo0
                    10.0.4.0/24        link#23            U        ovpns5
                    10.0.4.1           link#5             UHS         lo0
                    10.0.5.0/24        link#24            U        ovpns6
                    10.0.5.1           link#5             UHS         lo0
                    10.200.0.0/24      link#8             U       tun_wg0
                    10.200.0.1         link#5             UHS         lo0
                    xxxxxxxxxxxxxx     link#19            UH       pppoe0
                    yyyyyyyyyyyyy      link#5             UHS         lo0
                    127.0.0.1          link#5             UH          lo0
                    192.168.1.0/24     link#2             U           re1
                    192.168.1.1        link#5             UHS         lo0
                    192.168.2.0/30     link#1             U           re0
                    192.168.2.2        link#5             UHS         lo0
                    192.168.3.0/24     link#17            U       re2.106
                    192.168.3.1        link#5             UHS         lo0
                    192.168.6.0/24     link#20            U       bridge0
                    192.168.6.1        link#5             UHS         lo0
                    192.168.8.0/24     link#10            U       re2.201
                    192.168.8.1        link#5             UHS         lo0
                    192.168.9.0/24     link#16            U       re2.105
                    192.168.9.1        link#5             UHS         lo0
                    192.168.21.0/24    10.0.2.2           UGS      ovpns2
                    192.168.178.0/24   10.0.4.2           UGS      ovpns5
                    192.168.179.0/24   10.0.5.2           UGS      ovpns6
                    zzzzzzzzzzzzzz     link#19            UHS      pppoe0
                    
                    

                    Screenshot from 2023-07-04 18-47-12.png

                    Server on Site-B (first post) located at 10.0.0.0/24

                    machineMX log for incomming smtp connection:

                    postfix/smtpd[31491]: connect from mail.example.org[10.200.0.2]
                    

                    How to disable NAT to achieve this?:

                    postfix/smtpd[31491]: connect from mail.example.org[...real_IP...]
                    
                    B 1 Reply Last reply Reply Quote 0
                    • B
                      Bronko @Bronko
                      last edited by Bronko

                      @Bob-Dig said in NAT forwarding into WireGuard Interface as LAN Interface:

                      Don't NAT, like I said before and don't use haproxy for email.

                      Ok, but NAT on Site-A WAN interface is necessary for sure.

                      @viragomann said in NAT forwarding into WireGuard Interface as LAN Interface:

                      Anyway you would have to obey my suggestions regarding interface assignment and filter rules at B above.

                      I'm full in trust with you and and it's right in place....

                      V 1 Reply Last reply Reply Quote 0
                      • V
                        viragomann @Bronko
                        last edited by

                        @Bronko said in NAT forwarding into WireGuard Interface as LAN Interface:

                        what I would like to reach?

                        Still not clear, what this is and what you're doing exactly, even I requested several times. So I'm out here.

                        B 1 Reply Last reply Reply Quote 0
                        • B
                          Bronko @viragomann
                          last edited by Bronko

                          @viragomann said in NAT forwarding into WireGuard Interface as LAN Interface:

                          Still not clear, what this is and what you're doing exactly, even I requested several times. So I'm out here.

                          Oh, I'm sorry... my picture above should it sum up.
                          Recap: How to log on machineMX real source IP here:

                          postfix/smtpd[31491]: connect from mail.example.org[...real_IP...]
                          
                          B 1 Reply Last reply Reply Quote 0
                          • B
                            Bronko @Bronko
                            last edited by

                            I have been take some packet sniffs...

                            With outbound NAT rule @viragomann from above the source IP is replaced by pfsense tun_wg0 at Site-A (10.200.0.2) and machineMX reply is flowing back to Site-A; it works.

                            Without outbound NAT the real source IP is kept (what I would like to reach) and the machineMX is replying too (sniffed at LAN_SEITE3), but the reply doesn't dive into tun_wg0 back at Site-B, means only the smtp requests from real source IP are sniffed at tun_wg0. No firewall drops in system logs. "Allow any rules" are placed at tunnel and server net (LAN_SEITE3) as required.
                            How can I find where the smtp replies are dropped?

                            V 1 Reply Last reply Reply Quote 0
                            • V
                              viragomann @Bronko
                              last edited by

                              @Bronko
                              You mentioned above, that you run the SMTP traffic over HAproxy at A. Is that still the case???

                              1 Reply Last reply Reply Quote 0
                              • B
                                Bronko @Bronko
                                last edited by

                                @viragomann
                                No isn't:

                                @Bronko said in NAT forwarding into WireGuard Interface as LAN Interface:

                                .... but to use HAProxy as a reverse proxy for the Postfix SMTP server, you need to enable Postscreen in Postfix. This doesn't worked for me at the first run...

                                SMTP port forwarding for now, and it only works with outbound NAT rule at Site-A... (my last post).

                                B 1 Reply Last reply Reply Quote 0
                                • B
                                  Bronko @Bronko
                                  last edited by Bronko

                                  Because I'm going off topic here, I'm resuming what is still the problem at a new Topic and it solved there.

                                  1 Reply Last reply Reply Quote 0
                                  • First post
                                    Last post
                                  Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.