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

    IPsec Site-to-Site with NAT

    Scheduled Pinned Locked Moved IPsec
    28 Posts 3 Posters 2.5k 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.
    • DerelictD
      Derelict LAYER 8 Netgate
      last edited by

      The problem in that situation is generally that the far side will not route traffic back to arbitrary source addresses over the tunnel.

      You could outbound NAT on the IPsec tunnel there but that does not work with pfSense IPsec VTIs.

      OpenVPN would probably work for you if the USG has something equivalent to reply-to.

      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
      • J
        jf5264835
        last edited by

        In this case my USG side is setup to route traffic back to the pfSense at the 172.21.69.1. I'm trying to do policy based routing because I had read NAT doesn't work with IPsec VTI on pfSense. I have no clue how to go about setting up the outbound NAT correctly, I've tried and failed repeatedly. Wouldn't the outbound NAT be needed to translate traffic coming in on 54.39.14.0 to something that hosts on the USG side would be able to send traffic back to?

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

          Outbound NAT does not work on IPsec VTI interfaces.

          OpenVPN works.

          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
          • J
            jf5264835
            last edited by

            Ahh. I was under the impression that it would work if using an IPv4 tunnel rather than the VTI tunnel.

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

              You can many-to-one NAT or 1:1 NAT if you like on a policy-based tunnel. Just add the NAT address/network to the phase 2 entry.

              the other side will be configured with the NAT addresses as the remote network in the traffic selector.

              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
              • J
                jf5264835
                last edited by

                It's setup that way, it's a policy based tunnel but no source NAT is actually occuring, nor is any traffic flowing over the tunnel.

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

                  What is Address 54.39.14.0? That is a network address not a host address in almost all cases.

                  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
                  • J
                    jf5264835
                    last edited by

                    Its an IP provided by the hosting provider the pfSense box is running on, to be setup as a virtual/failover ip. They just assigned 8 ips rather than a routed block.

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

                      And how do you source connections from that address?

                      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
                      • J
                        jf5264835
                        last edited by

                        Screen Shot 2019-08-25 at 1.03.38 PM.png

                        They are just setup as Virtual IPs on the WAN interface. Browsing to one that hasn't been setup yet with 1:1 nat takes you to the pfSense login page (https://54.39.70.254/), and those addresses reply to ICMP requests, so I know that part is good.

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

                          Well whatever is set up on WAN has nothing to do with the IPsec NAT.

                          That configures what happens to the NAT in the tunnel itself.

                          When the other side connects to 172.21.69.1 what do you want to happen?

                          Specifically, what connecting to what is not working?

                          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
                          • J
                            jf5264835
                            last edited by

                            I want to be able to connect to say, 54.39.70.254 in a web browser, and have it show content from 172.21.0.11. From my understanding, I'd need source NAT for the incoming traffic, and a 1:1 NAT for traffic for External IP>Internal Host IP.

                            DerelictD 1 Reply Last reply Reply Quote 0
                            • DerelictD
                              Derelict LAYER 8 Netgate @jf5264835
                              last edited by

                              @jf5264835

                              jf5264835 less than a minute ago

                              I want to be able to connect to say, 54.39.70.254 in a web browser,

                              Connect to that from where?

                              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
                              • DerelictD
                                Derelict LAYER 8 Netgate
                                last edited by

                                If you are talking about connections coming into WAN then out over the IPsec to a server across the tunnel then that is not the correct method.

                                You would need to set the source on the phase 2 to Network 0.0.0.0/0 with a NAT to Address 54.39.14.0 to make that traffic interesting to IPsec. The WAN external 1:1 address in that case would be 54.39.70.254, not 54.39.70.0.

                                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
                                • J
                                  jf5264835
                                  last edited by

                                  Anywhere. Public IP address, so basically anywhere,anytime.

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

                                    When a connection attempt comes into WAN, the 1:1 NAT translates the destination address. When the connection goes out the IPsec tunnel the NAT there translates the source address.

                                    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
                                    • J
                                      jf5264835
                                      last edited by

                                      Screen Shot 2019-08-25 at 1.23.29 PM.png

                                      So I'd want the P2 to be like this?

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

                                        It has to be to have a hope of the traffic being put into IPsec at all.

                                        OpenVPN is much more flexible in this regard, but IPsec might be able to be coerced to work.

                                        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
                                        • J
                                          jf5264835
                                          last edited by

                                          Screen Shot 2019-08-25 at 1.57.13 PM.png

                                          ICMP comes in and gets NATed, but nothing goes through the IPsec tunnel.
                                          Screen Shot 2019-08-25 at 1.59.35 PM.png

                                          Time to try OpenVPN?

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

                                            That does not look like the traffic is being picked up by the traffic selectors after the NAT happens. It looks like it is just going back out the WAN.

                                            I was expecting you to be pinging .254 from the outside, not .0

                                            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
                                            • First post
                                              Last post
                                            Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.