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

    Communicate with an OpenVPN Client from behind the LAN

    Scheduled Pinned Locked Moved OpenVPN
    14 Posts 2 Posters 2.0k 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.
    • H
      Heli0s
      last edited by

      Is there a way to setup static IPs to OpenVPN clients and add those IPs to the DNS Forwarder?

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

        Don't see why not but it would probably be a two-step process.  I don't think there's a hook from OpenVPN into dnsmasq.

        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

          My tunnel network is 172.29.64.0/24.  I just added this to my client-specific override and it worked fine:

          ifconfig-push 172.29.64.100 255.255.255.0;

          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
          • H
            Heli0s
            last edited by

            How does the OpenVPN Server know which client should get which IP address?

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

              The common name in the certificate used to connect references the common name in a client-specific override which contains the ifconfig-push command.

              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
              • H
                Heli0s
                last edited by

                Completely missed that tab. Thanks! I do have two more quests:

                1. Is it possible to see when a client connects and what clients are currently connected?
                2. If I want to take away a client's access, do I just remove their cert or is there something else I need to do?
                1 Reply Last reply Reply Quote 0
                • DerelictD
                  Derelict LAYER 8 Netgate
                  last edited by

                  @Heli0s:

                  Completely missed that tab. Thanks! I do have two more quests:

                  1. Is it possible to see when a client connects and what clients are currently connected?

                  Status->OpenVPN?

                  There's also a dashboard widget I think.

                  1. If I want to take away a client's access, do I just remove their cert or is there something else I need to do?

                  Without requiring a username and password (which you could temporarily disable or change)  I'm pretty sure you're limited to revoking the cert and using a CRL.  System->Cert Manager Certificate Revocation.  You'll want to be sure OpenVPN is properly honoring the CRL by thoroughly testing.

                  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
                  • H
                    Heli0s
                    last edited by

                    So my server is 10.10.0.0/24 and I've added the following line to the client override: ifconfig-push 10.10.0.10 255.255.255.0;

                    But I'm getting the following error: ifconfig addresses are not in the same /30 subnet

                    1 Reply Last reply Reply Quote 0
                    • H
                      Heli0s
                      last edited by

                      Never mind. Apparently, you need to check the "Allocate only one IP per client (topology subnet), rather than an isolated subnet per client (topology net30)." checkbox in the server for this to work.

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

                        Or you need to statically assign based on topology net30.  I think it's something like ifconfig-push 10.10.0.9 10.10.0.10.

                        But if topology subnet works it's the preferred mode.  net30 is being deprecated I think.

                        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.